Fix small braino introduced while refactoring
Let private chat act as the bot's nick for triggering commands
Keep a reference to the bot itself in events

This allows the creation of introspective modules (and later perhaps even
control modules).
Add an introspection-based help system module
Merge remote-tracking branch 'upstream/master'
Add .WHY comments to modules and commands for the help system
Merge pull request #8 from japhb/master

Fix two minor bugs, and introduce an introspection-based help system (uses #= comments and the MRO)