Trying to validate basic display rendering

[jcorbin]

Iterating on internal/view/demo in #31, I've commented out the use of hud (to eliminate use of display.Draw so that I'm just using a fullscreen test pattern.

I have to disable colors to get "working" with Model0:

But things just disappear even with classic Model3:

Remain invisible until Model24 "gets weird":

This is the same sort of weirdness that you get even more of if you use the commented out fg/bg green/blue renditions.

[jcorbin]

Going to work the problem from the other end for a bit by factoring out a simpler display layer into cops ala the showroom proof first.

[jcorbin]

Update:

• Test and fix cops rendering through model8 #38 fixes basic 8-color rendering for sure
• I'm not yet sure about 24-bit color; will add a test case and better pattern in Add a testpattern proof #37
• display drawing still has something off about it, but will sort through that in WIP: cops-ified view system #31