Clear storage and branch preserves B register (Van Snyder)
Merge Fixes from Bob Supnik's updates
SCP: Fix Set Command dispatching and HELP dev SET output

 - Fixed set MTAB dispatching to not dispatch to unit specific routines when only a device is specified in the command
 - Fixed HELP dev SET output to avoid displaying SET commands which aren't valid for SHOW only cases
sim_sock.c allow validation address to match various forms of literal localhost addresses.
DDCMP: Reordered fields written in debug output for easier reading and fixed ddcmp_build_nak_packet to insert the flags value into the constructed packet.
TMXR: separate RTS from DTR when manipulating modem state bits
Merge branch 'master' of github.com:simh/simh into KDP
Merge branch 'master' of github.com:simh/simh into KDP
DMC: Fix DDCMP reset logic to properly clear and resend (later) pending transmits when the link state goes down.  Enable piggy-back ACKs when possible.
DMC: Fix typo.
DMC: Fix memory leak when buffers are reused. Fix recording of modem signal states.
DMC: Properly determine line connection status by referencing DCD instead of DSR
DMC: More fixes referring to DCD instead of DSR to reflection line connection state
README: Update to correct URL for windows binaries.  #70
TMXR: Enhance tmxr_set_get_modem_bits to also return the modem DTR and RTS state.
DMC: Fix DDCMP modulo 256 compare operations.  Fix to avoid potential memory leaks when device is programmatically reset.
PDP11/VAX: pdp11_hk Fix by Bob Supnik for issue #47

Revised error handling to command-response model
Revised interrupt logic to follow the hardware
Updated PDP11 and VAX780 documentation.
DMC: Added register descriptions and revised help.
DMC: Fix ddcmp Modulo 256 compare corner cases