Also: split out bcd predefs from yellow/main.asm, start removing traces
of W_

and other clean up

rename functions, clean up address/wram comments, other misc
only broken up so that all changes are viewable on github

This is mostly because of an rgbasm bug that prevents macro arguments
from exceeding 16 characters, but the names were bad anyway.

For unknown addresses, use "w<address>".

Label overleads are still an issue.