MediaLibrary with implementation for Windows Phone, iOS and Windows 8
Fixed linux build
Fixed android build
Fixed Album.HasArt on iOS
Simplified music playback on iOS
Fixed Song.Name on iOS
MediaLib will not return not downloaded iTunes Match songs on iOS
Merge branch 'MaxMipLevel' into develop
Fixed bug in detection of "natural" orientation of Android device.

Value of "natural" orientation is computed on first OnOrientationChanged() call (not in ctor, because it may return invalid value if called too early).
Orientation listener is active between Activity.OnResume()/OnPause() calls.
Orientation value of OrientationUnknown (-1) is ignored.
Fixed shifted drawing on KitKat after app resume.
Split PipelineController.Actions into code files for each action class.
Undo/Redo menu items are always in the correct 'Enabled' state. Previously they were only getting updated when an UpdateMenus call was triggered, which is much less frequent than we require.
Moved ActionStack declaration to within PipelineProject, it is only intended to be used by PipelineController not to be part of the public API.
ActionStack.Add(action) no longer calls action.Do, if the caller wants it can call Do prior to the Add.
Merge pull request #2629 from Nezz/medialib

MediaLibrary
Added MonoGame.Content.Builder.targets

MonoGame.Content.Builder.targets automatically builds all referenced
Content Projects
Fixed formatting
Merge pull request #2672 from queader/develop

 Added MonoGame.Content.Builder.targets to automatically build and redirect the output of referenced Content Projects
Implemented Undo/Redo for ContentItem modifications (done through the property grid).
Merge pull request #2678 from SickheadGames/UndoRedo

PipelineTool undo/redo
Fix PSM compile error.
Added tree-view context menu options 'Open File' and 'Open File Location'.
Added IProjectItem.OriginalPath.
- For PipelineProject this replaces FullPath
- For ContentItem this replaces SourceFile
- For FolderItem this is identical to Location
Added IController.GetFullPath(string) which returns the an absolute path given a project relative path (or returns unchanged path if already rooted).
Double clicking on a ContentItem will now 'Open File'.
Fixing typo, inverted conditional.
Merge pull request #2681 from SickheadGames/PipelineToolOpenFile

Adding 'Open File' and 'Open File Location' to PipelineTool tree context menu.