This happens before the SDL GL window is set up, which just
results in a warning. Another call will properly set the
gamma table after the window is initialized.
Make gammaTable a stack variable. This is sufficient, since SDL
already restores the gamma values for us on exit.
Don't include the lazy precompiled.h everywhere, only what's
required for the compilation unit.
platform.h needs to be included instead to provide all essential
defines and types.
All includes use the relative path to the neo or the game
specific root.
Move all idlib related includes from idlib/Lib.h to precompiled.h.
precompiled.h still exists for the MFC stuff in tools/.
Add some missing header guards.
