Revert changes to solution file

Visual Studio version in the solution file was changed by mistake to 14.0 in commit b82733. This commit reverts the version to 12.0

Author: Kapil Borle

PSScriptAnalyzer.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 14
-VisualStudioVersion = 14.0.25123.0
+# Visual Studio 2013
+VisualStudioVersion = 12.0.21005.1
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ScriptAnalyzerEngine", "Engine\ScriptAnalyzerEngine.csproj", "{F4BDE3D0-3EEF-4157-8A3E-722DF7ADEF60}"
 EndProject