Song.FilePath now an absolute path on desktop and Windows Store systems.
Song.Position and Song.FilePath are now internal as they are not part of XNA.
Added song support for Windows DX desktop builds.
Merge branch 'develop3d' into windesktop
Merge branch 'windesktop' of github.com:SickheadGames/MonoGame into windesktop
Merge pull request #1272 from SickheadGames/windesktop

Song Support for WinDX
Merge pull request #14 from mono/develop3d

Merge back from develop3d