common.h: Define a new function, ReGBA_GetBundledGameConfig.

DSTwo, GCW Zero: Implement the above function. Fix up includes in some files.

memory.c: Add main_path. Add the ability to look up game identification information in a bundled game_config.txt file.
GCW Zero: Implement the real-time clock.
GCW Zero: Bundle game_config.txt into the OPK package when building.
DSTwo, GCW Zero: Makefile cleanups.

Makefile.rules: Use $(ASFLAGS) when assembling.

mips/emit.h, mips/stub.S: Stop explaining the MIPS defines; they're now in dev-doc/defines.txt.
.gitignore cleanups.
Dingoo A320 (gcw0 directory): Fix a bug whereby flushing the cache causes a SIGILL.