Beta55 test release

Beta55 test release:

Fix new multicore NTSC artifact not working on Apple IIc and Apple IIe digital connection
Fix old NTSC artifact glitching on Apple IIc and Apple IIe digital connection with Pi zero
(Apple II analog connection not affected)

Add TRS80 model IV profile
Update various existing profiles

Update resolution files

Add test profiles for use with test jig

Fix multicore NTSC artifact not working on Pi 4