Fixed song bug.

This patch fixes strange song bug on WinDX platform. This bug is in the call of method MediaPlayer.Play. It play song once but at another time(closing and another runs of a game) - it emit exception at MediaFactory.GetService in internal PlaySong method - "Not supported Interface". Probably this is Sharpdx internal problem. This is workaround this bug. In debug mode when you set debugging point on this method it load interfaces correctly but if not - this exception emits. If you call it once again after this exception - it loads correctly. Also im added Obsolete atribute to Keyboard.GetState(PlayerIndex) - this method is dublicate GetState and must be deleted in a future versions - I marked it obsolete for make attention for developers.