[Simh] PDP8 changes

[David Gesswein]

   I'm not sure where simh development is discussed with the move to
github. I submitted a couple of bug but I have some other changes I
have made to my version and want to see if they are of interest.

1) Modify bin loader to read multiple section tapes.
2) Modify breakpoint command to add breakpoint on instruction value.
3) Raw socket for teletype console instead of telnet wrapped.