* Don't show artifacted colours for CSS=0.
* Better emulation of undocumented 6809 behaviour.
* New joystick axis and button mapping options.
* Add GTK+-2 file requester.
* Mid-instruction peripheral state sync.
* Restructure CPU core to more accurately reflect data sheet.
* PIA code not so intimately tied to emulator code.
* New 5-bit NTSC cross-colour renderer.
* NTSC cross-colour phase saved with snapshots.