Merge branch 'jspenguin-master'
Put output files in the CMake binary directory (to allow multiple builds from the same source directory)
Put vrquake2.pk3 in the CMake binary output directory
Don't re-generate vrquake2.pk3 if it is already up-to-date
Add floating HUD
Enable SRGB on all platforms; retry window creation without SRGB if it fails
Fix uninitialized variable usage in weapon_bfg_fire