Generating colour bars with minimal resources

[ppppenguin]

Had 1 more go before switching off and bingo! We have bars. There are a few problems but nothing too bad.Tthe blue chroma amplitude is wrong and I've already found the typo that caused it. There will be some timing refinements to be done and I may be able to smooth off the sharp edges a little bit. I need to sort output filtering and sin(x)/x correction. Basically those bars are already just about good enough for telly mending.

Another question is will the design fit in the CPLD when I add back the logic that handles the control panel of the Museum's video/audio router. Seeing as test pattern generation is a secondary function it feels like the pattern generator tail is wagging the controller dog.