Minor improvements.
Minor improvements.

- Removed Y border
- Fixed attribute offset on reg(9) = 0
- little adjustment to busyFlagClearCycle delay in case of writing on reg(31)
- on copyfill operation now the delay depends on copy or fill operation
- added handling of forced vsync if vsync is out of screen
- currentCharScanLine & rowCounterY are now limited to 31

abbruzze/kernal64,abbruzze/kernal64,abbruzze/kernal64