[Coco] VCC enhancement request

[Robert Gault]

There have already been requests for better artifact color display with the composite monitor 
setting with the VCC emulator, which I second.

More to the point all emulators which do provide artifact colors at least as good as MESS/MAME only 
generate them on PMODE4 screens. A real Coco3 will, with an NTSC composite monitor, generate 
artifact colors on any screen including an HSCREEN such as HSCREEN4 640x192x4 and with $FF9F HVEN 
set the 640x256x4.

So if anyone is planning to improve the VCC video, please include artifact colors on the HSCREENs 
while working to improve the same on the PMODE screens.

Robert