small wip
which means I (almost) fixed the sprite limit flags.
since the changes are quite large, I will probably wait until 0.137 is out before commit, to avoid any last minute apocalypse
EDIT: further tests show that the new OAM code fixes also the missing Mario sprite at the upper-left corner of world map in SMW. the reported priority problems in TMNT and Chrono Trigger are not fixed though and a few glitches have been introduced in at least R-Type 3... more work is needed on the sprites