[test_roms] generate linear mem text file
[test_roms] set 4 palette colors and count up on the debug port
[sggoc] remove trailing comma
[sggoc] fix bg_color bitwidth
[sggoc] fix vdp <-> z80 control logic. palette test works now.
[sggoc] explicitly enable fast registers on the FL_* lines. (not sure if needed)
[sim] added z80+vdp testbench
[sggoc] increase clock speed / set green leds back to z80 status lines