* Added OSX platform to MGSongProcessor.cs to compress mp3 songs
* MonoGame on MAC throws a notimplementedexception on IPv4Mask, so we return null on Mac Implementation. Had to add a MONOMAC define to the project.
Revert "* Added OSX platform to MGSongProcessor.cs to compress mp3 songs"

This reverts commit 642827f4c82bb9226055a69532701ad2907fdaea.
Fixed up XAudio shutdown for DX desktop platform.
Inlined the vector math in BoundingBox.CreateMerged().
Fixed some BoundingBox methods to make the ref versions faster.
Inlined Vector3.Equals() for less method call overhead.
Fixed duplicate code in Matrix, now non-ref methods call the ref methods.
We now retry creation of the DirectX device without the debug flag.
Merge branch 'develop' into math_opt
Fix for "NullReferenceException when creating a Game instance" on iOS after update to Xamarin.iOS 6.4.4.12
Removed unused XML references on Android Project.
Removed unused XML references on iOS Project.
Removed unused XML references on Ouya Project.
Removed unused XML references on Linux Project.
Removed unused XML references on MacOS Project.
Removed unused XML references on WindowsGL Project.
Removed unused XML references on Windows Project.
Merge pull request #1977 from SickheadGames/dxdebug

DirectX Debug Mode Fallback
Also removed System.Xml references on Lidgren.
Added back Lidgren references to System.Xml, since it needs it.