compiling direct x version

[Bigpet]

@raintime, I didn't write any of the directx code anyway, most of the incomplete directx backend code that is in the repository now is from Ced2911 who worked on a XBox360 port but got dis-interested. I never tried to write a directx backend, I just tested how Angle would perform out of curiosity (and later because I needed it to test the multi-touch windows simulator)