New opengl thread context selection patches for testing

[Stefan Dösinger]

Hi,
Here is a new patchset for testing which implements duplicating gl contexts 
for new threads in wined3d. Again, it does not implement any synchronisation 
measures(except ENTER_GL and glFinish), so running multithreaded games is 
still kinda a lottery.

This patchset also contains a patch for offscreen rendering, which may fix the 
problems introduced with TES: Oblivion before.

This is just a format-patch of my git tree, the first 3 patches are unrelated. 
One of them is a clone of Henri's already sent patch, and the other 2 patches 
were sent by me already.

Happy testing,
Stefan