* Add cotire cmake module to speedup compilation https://github.com/sakra/cotire
* Fix clang error and warnings
* Rename Font to BitmapFont to fix conflict with Xlib.g Font typedef
* Remove legacy PCH support
* Improve Position hash
* option to pass -opengl1 or -opengl2 as argument
* note that with this commit there are a lot of graphics regressions and the master will remaing unstable for a while
* shaders disabled for a while