Enhancements to inter-BBS instant message module:

- less verbose startup (don't display every system being pinged)
- store the info for the last sent message and use that or the last
  received message to automatically fill in the recipient of telegrams.

This entire module could still use some re-write. It'd be nice if it
automatically re-pinged all the systems and displayed newly discovered
users or those who have apparently logged-off.