Aaron Campbell <aaron@cs.dal.ca>.
Use SHIFT-PgUp and SHIFT-PgDn to scroll back and forward.
Aarons original code was enhanced to have a separate scrollbuffer
for every virtual terminal and to preserve the screen contents
when switching screen sizes.
The scrollbuffer size is currently fixed at 8 pages but this
will be made configurable through the use of scon(1) in the
near future.
For pcvt_kbd.h, a longstanding compiler warning was fixed by
using excessive backetizing of the key2ascii[] table.
