Sec/medical HUD users now receive relevant broadcasts

Users of security HUDs now receive broadcast messages from security bots. Similarly, users of medical HUDs receive broadcast messages from medical bots.
These messages can be enabled/disabled for individual bots through their standard configuration menu.

![Freeze, scumbag](https://www.dropbox.com/s/perfsp2lfo58u64/BotBroadcast.png?dl=1)

Also fixes a runtime error detected during development.