These drivers are almost directly from VOGLE. The only change that has
been made to them is to enable a viewport clearing function (as opposed to
clearing the whole screen).

Most of the line drawing and text routines for PC's comes from the book

 "Programmers Guide to PC & PS/2 Video Systems" by Richard Wilton

Some other stuff came from the book

 "Programmers Guide to Hercules Graphics Cards" by David B. Doty

and some other stuff was filtched from J.D. McDonalds Fastega libarary

and last but not least, we made up lots of stuff ourselves.

