Added Sample for NV_DX_interop (FastGL)

The sample has some known limitations:
 - resizing the scene doesn't work properly yet
 - Code has to be cleaned, I extracted it from our Codebase
 - probally a lot of yet unknown bugs, DirectX can be an asshole and there
   is little to know documentation for NV_DX_interop (and even what exists
   is incomplete ...)

This is only working on GPUs supporting DirectX9 and only in Windows Vista
and newer. The Windows-version-issue can be fixed with some work (using
Device on Windows older than Vista and DeviceEx on Vista and newer).