Default NVRAM contents
Save default NVRAM contents
Obey XON/XOFF flow control from VT100
Fork off a shell on our new pty.
Adjust -r to switch to Typing mode too
Slow down CPU processing to 1MHz

This makes the VT100 flash it's cursor and process characters at about
the right speed. The CPU can accept characters at about 4800baud without
flow control which matches other documentation.

This is despite other documentation that says the CPU runs at 2.765 MHz.

The key debounce routine is eating repeat codes though.
More keyboard codes available.

Make some explicit mappings for Function keys that don't exist on the
VT100
    F5  - Linefeed (Return sends ^M)
    F6  - Escape KEY (rather than Ctrl-[)
    F7  - BREAK
    F9  - Shift-BREAK
    F9  - Setup
    F10 - Command Key
    F11 - Keycode generator (see source).

Add control keys, including all control keys.
Adjust display look

VT100 screen is set to green,
VT Graphics has a good chance of working.
Make the LED colours a bit more obvious (and flip ONLINE/LOCAL)
Merge pull request #1 from rdebath/master

Some nice emulator patches