HP-35/45 Simulator for PDP-8

[Kyle Owen]

I updated the project to include optional OS/8 support. I won't say I've
tested it extensively, but it does seem to be working as expected in SimH,
anyways. I updated the README to reflect the additions. The directory
structure was also updated to something more sane.

The keen observer will note that I also changed up some of the debugging
features which are likely to not be useful to anyone other than the
author...and even then, I only used the features a few times when getting
the thing running initially. But, it's there if you need it, all
configurable through the switch register as detailed in the source.

Glad some folks got a kick out of it enough to try it out! Feel free to
suggest improvements where you see fit. I was thinking about adding support
to read keystrokes from a file for macro programmability...but that might
be too absurd even for this project. Maybe the HP-41C simulator is next...
:)

Kyle