The game now successfully compiles and runs on linux using CMake

- Fixed qagame-rtcw.so being compiled with "CGAMEDLL" defined instead of "GAMEDLL" defined (caused a load issue at runtime)
- Added GtkRadiant submodule to successfully compile the GtkRadiant section of the game
- Fixed all the bspc sources to use new build system includes
- Fixed some CMake build definitions not being applied
- Attempted to identify number of cores the system has and the CPU string used but seems to have failed
- Fixed clang compiles
- Cleaned up MANY warnings that were a result of carelessness
- Ignore a warning for clang (and maybe gcc too - didn't check) where we cause a null-dereference on purpose to force a crash