SCP: Initial merge of old style single line help with hierarchical help
SWTP: Fixes to segfault issue described in #103 (from Gene Irwin)

The simulated memory address block from 0x8000 thru 0x8FFF is defined to have address 0x8000 - 0x801F mapped to I/O ports and 0x8020 - 0x8FFF as NO RAM ALLOWED.  Code has been added to behave reasonably when references are made to 0x8020 - 0x8FFF.