Change BSPC version back to 2.1h, 2.2 is used by RTCW's BSPC

Spearmint BSPC doesn't support RTCW, so let's try to avoid some version number confusion...
BSPC ifdef cleanup
Load window icon from game file system

Windows uses 32x32 icon, Linux uses larger (1024x1024 seems ok).

Icon selected by r_forceWindowIcon32 cvar.
Merge remote-tracking branch 'spearmint/master'
Revert built-in window icon to ioq3 icon