Added PCL projects and linked sample droid project to it

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/App.xaml

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+<?xml version="1.0" encoding="utf-8" ?>
+<Application x:Class="XFShimmerLayoutPCLSample.App" xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" />

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/App.xaml.cs

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+using Xamarin.Essentials;
+using Xamarin.Forms.Xaml;
+using XFShimmerLayoutPCLSample.Controls;
+
+[assembly: XamlCompilation(XamlCompilationOptions.Compile)]
+namespace XFShimmerLayoutPCLSample
+{
+    public partial class App
+    {
+        public App()
+        {
+            InitializeComponent();
+
+            ShimmerLayout.Init(DeviceDisplay.ScreenMetrics.Density);
+
+            MainPage = new Views.ShimmerTestPage();
+        }
+    }
+}

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/Models/NotifyingObject.cs

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+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using Xamarin.Forms;
+
+namespace XFShimmerLayoutPCLSample.Models
+{
+    public class NotifyingObject : BindableObject
+    {
+        private readonly Dictionary<string, object> _properties;
+
+        public NotifyingObject()
+        {
+            _properties = new Dictionary<string, object>();
+        }
+
+        #region [Notify Property Changed]
+
+        protected virtual bool Set<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
+        {
+            if (EqualityComparer<T>.Default.Equals(storage, value)) return false;
+
+            storage = value;
+            OnPropertyChanged(propertyName);
+            return true;
+        }
+
+        #endregion
+    }
+}

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/Properties/AssemblyInfo.cs

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+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+// Information about this assembly is defined by the following attributes. 
+// Change them to the values specific to your project.
+
+[assembly: AssemblyTitle("XFShimmerLayoutPCLSample")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("")]
+[assembly: AssemblyCopyright("${AuthorCopyright}")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// The assembly version has the format "{Major}.{Minor}.{Build}.{Revision}".
+// The form "{Major}.{Minor}.*" will automatically update the build and revision,
+// and "{Major}.{Minor}.{Build}.*" will update just the revision.
+
+[assembly: AssemblyVersion("1.0.*")]
+
+// The following attributes are used to specify the signing key for the assembly, 
+// if desired. See the Mono documentation for more information about signing.
+
+//[assembly: AssemblyDelaySign(false)]
+//[assembly: AssemblyKeyFile("")]

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/ViewModels/ShimmerTestPageViewModel.cs

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+using System.Threading.Tasks;
+using Xamarin.Forms;
+using XFShimmerLayoutPCLSample.Models;
+
+namespace XFShimmerLayoutPCLSample.ViewModels
+{
+    public class ShimmerTestPageViewModel : NotifyingObject
+    {
+        private bool _isBusy;
+        public bool IsBusy
+        {
+            get => _isBusy;
+            set => Set(ref _isBusy, value);
+        }
+
+        private Command _startAnimationCommand;
+        public Command StartAnimationCommand
+        {
+            get => _startAnimationCommand;
+            set => Set(ref _startAnimationCommand, value);
+        }
+
+        public ShimmerTestPageViewModel()
+        {
+            StartAnimationCommand = new Command(async () =>
+            {
+                IsBusy = true;
+
+                await Task.Delay(5000);
+
+                IsBusy = false;
+            });
+        }
+    }
+}

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/Views/ShimmerTestPage.xaml

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+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage
+    x:Class="XFShimmerLayoutPCLSample.Views.ShimmerTestPage"
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:controls="clr-namespace:XFShimmerLayoutPCLSample.Controls;assembly=XFShimmerLayoutPCLSample"
+    xmlns:viewModels="clr-namespace:XFShimmerLayoutPCLSample.ViewModels;assembly=XFShimmerLayoutPCLSample">
+    <ContentPage.BindingContext>
+        <!--  For Test Reasons binding context is set through this way. Better use a DI Container  -->
+        <viewModels:ShimmerTestPageViewModel />
+    </ContentPage.BindingContext>
+    <StackLayout
+        Padding="16"
+        HorizontalOptions="Center"
+        Spacing="16"
+        VerticalOptions="Center">
+        <controls:ShimmerLayout Angle="-45" GradientSize=".2" IsLoading="{Binding IsBusy}">
+            <StackLayout Spacing="16">
+                <Grid ColumnSpacing="8" RowSpacing="4">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto" />
+                        <RowDefinition Height="Auto" />
+                    </Grid.RowDefinitions>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto" />
+                        <ColumnDefinition Width="*" />
+                        <ColumnDefinition Width="Auto" />
+                    </Grid.ColumnDefinitions>
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.RowSpan="2"
+                        Grid.Column="0"
+                        BackgroundColor="Brown"
+                        CornerRadius="20"
+                        HeightRequest="40"
+                        VerticalOptions="Center"
+                        WidthRequest="40" />
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="20"
+                        HorizontalOptions="Start"
+                        WidthRequest="150" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="14"
+                        HorizontalOptions="Start"
+                        VerticalOptions="Center"
+                        WidthRequest="50" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="2"
+                        BackgroundColor="Brown"
+                        HeightRequest="18"
+                        HorizontalOptions="End"
+                        VerticalOptions="Center"
+                        WidthRequest="100" />
+                </Grid>
+
+                <Grid ColumnSpacing="8" RowSpacing="4">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto" />
+                        <RowDefinition Height="Auto" />
+                    </Grid.RowDefinitions>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto" />
+                        <ColumnDefinition Width="*" />
+                        <ColumnDefinition Width="Auto" />
+                    </Grid.ColumnDefinitions>
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.RowSpan="2"
+                        Grid.Column="0"
+                        BackgroundColor="Brown"
+                        CornerRadius="20"
+                        HeightRequest="40"
+                        VerticalOptions="Center"
+                        WidthRequest="40" />
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="20"
+                        HorizontalOptions="Start"
+                        WidthRequest="150" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="14"
+                        HorizontalOptions="Start"
+                        VerticalOptions="Center"
+                        WidthRequest="50" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="2"
+                        BackgroundColor="Brown"
+                        HeightRequest="18"
+                        HorizontalOptions="End"
+                        VerticalOptions="Center"
+                        WidthRequest="100" />
+                </Grid>
+
+                <Grid ColumnSpacing="8" RowSpacing="4">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto" />
+                        <RowDefinition Height="Auto" />
+                    </Grid.RowDefinitions>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto" />
+                        <ColumnDefinition Width="*" />
+                        <ColumnDefinition Width="Auto" />
+                    </Grid.ColumnDefinitions>
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.RowSpan="2"
+                        Grid.Column="0"
+                        BackgroundColor="Brown"
+                        CornerRadius="20"
+                        HeightRequest="40"
+                        VerticalOptions="Center"
+                        WidthRequest="40" />
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="20"
+                        HorizontalOptions="Start"
+                        WidthRequest="150" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="14"
+                        HorizontalOptions="Start"
+                        VerticalOptions="Center"
+                        WidthRequest="50" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="2"
+                        BackgroundColor="Brown"
+                        HeightRequest="18"
+                        HorizontalOptions="End"
+                        VerticalOptions="Center"
+                        WidthRequest="100" />
+                </Grid>
+
+                <Grid ColumnSpacing="8" RowSpacing="4">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto" />
+                        <RowDefinition Height="Auto" />
+                    </Grid.RowDefinitions>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto" />
+                        <ColumnDefinition Width="*" />
+                        <ColumnDefinition Width="Auto" />
+                    </Grid.ColumnDefinitions>
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.RowSpan="2"
+                        Grid.Column="0"
+                        BackgroundColor="Brown"
+                        CornerRadius="20"
+                        HeightRequest="40"
+                        VerticalOptions="Center"
+                        WidthRequest="40" />
+
+                    <BoxView
+                        Grid.Row="0"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="20"
+                        HorizontalOptions="Start"
+                        WidthRequest="150" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="1"
+                        BackgroundColor="Brown"
+                        HeightRequest="14"
+                        HorizontalOptions="Start"
+                        VerticalOptions="Center"
+                        WidthRequest="50" />
+
+                    <BoxView
+                        Grid.Row="1"
+                        Grid.Column="2"
+                        BackgroundColor="Brown"
+                        HeightRequest="18"
+                        HorizontalOptions="End"
+                        VerticalOptions="Center"
+                        WidthRequest="100" />
+                </Grid>
+            </StackLayout>
+        </controls:ShimmerLayout>
+
+        <Button
+            Padding="8"
+            BackgroundColor="DarkCyan"
+            Command="{Binding StartAnimationCommand}"
+            CornerRadius="10"
+            HorizontalOptions="FillAndExpand"
+            Text="Start Animation"
+            TextColor="White" />
+    </StackLayout>
+</ContentPage>

src/Sample/XFShimmerLayoutSample/XFShimmerLayoutPCLSample/Views/ShimmerTestPage.xaml.cs

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+using Xamarin.Forms.Xaml;
+
+namespace XFShimmerLayoutPCLSample.Views
+{
+    [XamlCompilation(XamlCompilationOptions.Compile)]
+    public partial class ShimmerTestPage
+    {
+        public ShimmerTestPage()
+        {
+            InitializeComponent();
+        }
+    }
+}