1. The 'irc' mod options value was toggling the 'I' command key, not 'R'
   ('R' is for IRC, not 'I')
2. Use load({}, "sbbsimsg.js") so that the chat_sec options aren't blown-away
   by sbbsimsg.js

Enhancement:
- added support for 'imsg' option in [chat_sec] section of modopts.ini, if set
  to false, disables the inter-bbs instant message command key.