Core:
- added Win64 detection (DetectWOW64())
- added FPU_EXCEPTIONS define to allow/disallow FPU exceptions

OpenGLDrv:
- InitLightGrid() will no more cause OutOfMemory() when loading maps with large environments (example:
  Q3 "13cube.bsp" has very large skybox replacement)
- fixed crash (stack array overflow) in AddSkyTris(): increased MAX_CLIP_VERTS (64->256), added assert
- using sin/cos instead of table functions for TCMOD_ROTATE for smoother rotations

Miscellaneous:
- sys_win.cpp: do not compile guards when DO_GUARD=0
- updated genmake
- FontGen now can save font in .cpp format
- added .gitignore