swap clocks on ports on fastram.
clean up and fix clock bug for fastram.
cleanup debug function
cleanup debug function
clean up fastram interface management and some debugging.
fix bug where screen memory was being ignored.
modify default screen addresses so that they sit in the power-on
memory map.
move character cycling loop to point to memory in screen RAM.
allow CPU to run at full speed.
drop CPU clock from dotclock/2 to dotclock/4 in attempt to obtain
timing closure.