- CMD_RESPONSE now includes support for setting a mode to be set in the
  calling ACCOUNT object to facilitate MODE_DISCONNECT and MODE_NOECHO.
- COMMAND_D now maintains a standard CMD_RESPONSE object that is
  returned as a success marker from the process_command function, or nil
  for failure. Previously nil marked success while a string marked a
  failure. This does break the alias system for now though. Nothing yet
  makes use of this returned object either.