We don't want to modify emulation code yet as ISC support included
a number of other things, including some i386 code that isn't used
on other platforms, but is still useful as a reference.
This also removes support for the DEC3100 keyboard, but leaves a
constant behind for it as I'm not sure about re-numbering.
[NBriggs: keyboard type numbers are stored within all sysouts. Do not renumber supported keyboards, do not reuse previously used keyboard numbers]
This removes code related to HP9000, HPTIMERBUG, and HPUX defines.
It leaves KB_HP9000 for now as I'm not sure about renumbering
those constants.
This should not impact any of the core emulation code.
