Resolving Conflict.
Fixing WINGL build.
Fixing WINRT build.
Improvement pack for monogame.
Texture2D: Fix OpenGL GetData with null Rect
Fix for Android's Mouse.GetState().
Merge branch 'develop' into MultiWindowMouseInput

Conflicts:
	MonoGame.Framework/Windows/WinFormsGameWindow.cs
Merge pull request #1749 from SickheadGames/MultiWindowMouseInput

Multi-Window Mouse Input
Fixed crash when secondary GameWindow doesn't handle KeyState.
Merge pull request #1824 from SickheadGames/keyfix2

Fixed GameWindow Crash
Merge pull request #1817 from flibitijibibo/texture2d-gl-getdata

Texture2D: Fix OpenGL GetData with null Rect
Merge pull request #1810 from Shqrdx/develop

Improvement pack for monogame.