Fixed exception when using Song class before MediaManager is initialised.
Added shutdown of media manager when game exits.
Update MediaManagerState.cs

Removed thread safety checks from media manager, as it should only be started or stopped from the UI thread anyway.

Caller should be responsible for ensuring this.
Resolving Conflict.
Fixing WINGL build.
Fixing WINRT build.
Merged with Upstream
Improvement pack for monogame.
Merge pull request #1816 from sys27/develop

#1809 Remove CompilerOptions.cs
Texture2D: Fix OpenGL GetData with null Rect
Merge branch 'develop' of https://github.com/SimonPStevens/MonoGame into SimonPStevens-develop

Conflicts:
	MonoGame.Framework/Media/MediaPlayer.cs
Merge branch 'PR_1509_UPDATE' of https://github.com/totallyeviljake/MonoGame into totallyeviljake-PR_1509_UPDATE
Merge pull request #1820 from totallyeviljake/PR_1509_UPDATE

#1509 Updated to resolve conflict - verified by @borrillis
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
Added an overload to SpriteBatch.Draw()
Revised comment and removed pointless newline