Fixed SongReader and VideoReader not supporting parent directories (../Something)
Implemented GraphicsDevice.Reset, Windows/DirectX only.
Fixed bug causing 'new item' to not work outside the root directory.
Icons specified in template files are now actually loaded.
Added icon for XmlContent template.
NewContentDialog must more attractive now. Displays template items in a ListView instead of a ListBox, and shows their icons.
Templates loaded from a subfolder of the search path were not correctly resolving the fullpath.
Fixing mac build.
Merge pull request #3005 from SickheadGames/NewItemImprovements

Improvements to 'New Content' dialog.
Merge pull request #2996 from SickheadGames/GraphicsDevice.Reset

Implemented GraphicsDevice.Reset, Windows/DirectX only.
Merge pull request #2982 from SongArc/feature/readerfix

Fixed SongReader and VideoReader not supporting parent directories
Merge back from develop. TODO: GraphicsDevice.Reset
Lots of GraphicsDevice/GLDevice reorganization, Reset implemented
Remove MiniTK use in SDL2_GamePlatform
Offload GUID string collection to device init