begin adding cpu far call stack
4KB far call stack (512 x 64 bit entries)
fix plumbing of farcallstack
add iomap marker
add documentation for kickstart ROM and hypervisor trap entry point
try to fix 16-bit character mode attribute fetching from colourram.
also make attribute layout saner, and increase glyph number range
to 13-bits, so we can have 8,192 mono characters (=64KB), as well
as eventually supporting 8,192*64 = 512KB chipram containing glyphs..
fix glyph_trim_* signal type mismatch
fix multiple drivers
really fix multiple driver problem