classics fixed
frame.h for older ffmpeg
ffmpeg r_frame_rate -> avg_frame_rate
steam api specific calls fixed
steam api leaderboards made optional
Removed include of SDL_syswm.h because it creates problems on Kubuntu 14.04 with Mir
Removed ARB endings from OpenGL calls
Added check for Gallium drivers to use GLSL ES 3.00. #137
steam api disabled
png custom io hander var renamed
sdl includes simplified
ffmpeg includes simplified
Make it work with SDL2

cmake will set a -I/path/to/include/SDL cflag, so we can #include <SDL.h>
directly (which even works for both SDL1.2 and SDL2 then)
Merge branch 'rmPrecompiledHeaders'

Conflicts:
	neo/sys/posix/posix_main.cpp
	neo/sys/sdl/sdl_glimp.cpp
rebased