1.4.5: Fix the error when only one data (#152)

If the list just one data，spinner can’t show anything

1.4.4

• Fix Spinner's wrong behaviour when displayed in a dialog.

1.4.3: Mutate the arrow drawable to avoid inconsistent shared states

As the arrow drawable is usually mutated by the animator, it's better to create a copy of its state to avoid animation gliches and arrows in inconsistent states.

1.4.2

Change SpinnerTextFormatter to accept generic parameters

1.4.1: Fix wrong position passed through listeners

Revert one of the last changes to pass again the right 'position' value as a parameter of listener callback method.
Due the nature of the spinner, a method call to `parent.getItemAtPosition` will return a wrong value, though, as the entries displayed by the pop-up list and the ones contained in the adapter are different: the selected item won't be displayed within the list.

To avoid getting a wrong value from the parent, I've deprecated the current listeners interface and created a brand new one that solves the problem. The sample project app has been update to show the new approach.

Also, added two suite of tests to test the selection logic and the listener.

1.4

• Add the option to override method format() from SimpleSpinnerTextFormatter with generic Object class.
• Fix the wrong position passed when an entry from the list is selected.
• Add the option to load the data source from XML.

Fix ObjectAnimation crash on devices with version Kitkat or lower

Fix a objAnimation crash on Kitkat and below (#104)

Fix a crash when objAnimation is not supported and the device's version is lower than `KITKAT 4.4`.

Cancel the arrow's animation when the view is detached

Cancel the arrow's animation when the view is detached, so to avoid null pointer exception crashes for updating a null view.

1.3.6

Add an option to change the popup default text horizontal alignment

1.3.5: Include sample-app (#100)

* Edit the project's structure to include a sample app
* Add some layout
* Some gradle bump-ups