GPU: Updated g_last_ticks variable to be more descriptive (represents CPU tick count of last vertical line).

- Various other cleanups.

Core: Added a comment to explain the logic for the RunLoop iterations.

Also makes the illogical component order more obvious.

- added hooks to catch LCD IO read/writes

changed hw_lcd to use ARM core correct tick counter instead of [what was actually] just an instruction count. this seems to fix timing issues with the 3DS_Homebrew_Pong3Dv2 demo.