Every Statistics counter, the projection copies and the widescreen ratio
averages were only written since the debug UI went; the counters bumped
per primitive, per triangle and per pixel in the software rasterizer.
The widescreen heuristic keeps only the two vertex counts it compares,
from one projection/viewport ratio per flush instead of up to three.
GetCPRegInfo, the CP register describer, has no caller.
Instead, we make the event take a reference to the system and then pass
it in when the event is triggered.
This does introduce two other accessors, but these are much easier to
refactor out over time, and without modification to the existing event
interface.