memory.c, memory.h: Move timer functions from gpsp_main.c (per-platform) to here. Change savefast and SAVESTATE_FAST to "rewind" so they make more sense. Replace calls to fopen, fread, fwrite and fclose to the FILE_OPEN, FILE_READ, FILE_WRITE and FILE_CLOSE macros. Replace FILE_ID with FILE_TAG_TYPE. Remove references to init_progress(), show_progress() and update_progress(). Use a new function called ReGBA_LoadRTCTime to feed the GBA RTC and the saved state header.

draw.c: Remove 3 unused functions.

zip.c: Fix a bug whereby uncompressed ZIP entries were not loaded if they were larger than the Game Pak buffer. Fix three casts of pointers to u32 in calls to free().

common.h, dstwo/port.h: Move 2 DSTwo-specific headers from common.h to dstwo/port.h. Declare a new port function in common.h called ReGBA_LoadRTCTime; define it in dstwo/port.h.
memory.c, memory.h: Move to the cross-platform directory.
DSTwo: message.h, TEMPGBA/SYSTEM/language.msg: Remove MSG_UNCERTAIN from the message list.