Initial public version of Manchester SSEM for SIMH

Initial public version of Manchester University Small Scale Experimental
Machine (SSEM) for SIMH
Avoid passing negative values (i.e. signed characters) to isprint() which is not happy with doing this on some platforms.
Fix to avoid remote console looping in Multi-Command mode (Fix to issue #50).
SSEM documentation added

Documentation added. Copyright information addedd/corrected.
Enhanced remote console to display the simulator's prompt string in the remote console sessions and changed startup message to more clearly describe how to get into multiple command mode.
enhanced the relatively new tmxr_linemsgf api to dynamically flush a completely full transmit buffer as needed.
Merge https://github.com/simh/simh
makefile fix to produce consistent CC command for all targets
Added CR-LF line endings. Tabs replaced with spaces

Text files stored with CR-LF line endings, all tabs replaced with 4
spaces.
Merge https://github.com/simh/simh
LF endings replaced with CR-LF endings

Source file LF endings replaced with CR-LF endings. GIT configuration
changed: git config --global core.autocrlf false
Added build support for the new SSEM simulator and fixed minor compiler suggested cleanups
Merge branch 'master' into BlinkenLights