Various additions and fixes

Additions:

Offset-per-tile for modes using 8x8 tiles (Tetris Attack, Contra 3,
Chrono Trigger, Lufia II, ...)
Mode 7 variation with graphic priority bit (Contra 3, ...)
Mode 7 flipping attributes
Mode 5/6 in true hi-res (Secret of Mana, ...). Includes Interlacing.
Small Sprites

Fixes:

Windowing where one window fully overlaps another (Megaman X, Final
Fantasy IV & V, ...)
Sprites using tile numbers greater than 255 (Actraiser?, Contra 3, ...)
Mid-frame HDMA (Super Ghouls 'n Ghosts, ...)
Fixed Double windowing
Mode 7 junk

Fixed a slight problem when BG/OBJ layers are rendered in Mode 7. Also
reduced Mode7 memory requirements to two buffers instead of three, and
allowed both buffers to be used as necessary at the same time.
Merge pull request #7 from DiscostewSM/Hardware-Additions

Various additions and fixes