All registers required by the C167 interface have been added and tested

added lib treg8 for registers associated with C167 interface
all registers required by C167 microprocessor interface added and tested

The C167 interface was changed to address-based rather than select-line based
All registers required by C167 microprocessor interface added and tested

also commented our a fair amount of code related to VLBA design.  It can likely be deleted at a later date.
Made input clock to MMCM selectable via C167 interface register 0 bit 0.
C167 interface changed to address-based rather than select-line based.