* temporarily disable speedhacking (it gave little to no benefit and partially broke HDMA)
* PPU windows! although not finished (OBJ windows not done yet)
* bugs with 16x16 tiles :(
* emulate 2184-21FF open bus (fixes character test in SNES test ROM)
* revert to -O2, -O3 gives no improvement (and larger code has a higher chance of cache misses)