cba-bot: Rename from PyIRCBridge.py

This is much more descriptive, and sheds some legacy.
README: Document setup better

The documentation now includes basic configuration, and tells how to
go about debugging the bot.
Merge branch 'master' of heroku.com:hhpdonorbot

Conflicts:
	PyIRCBridge.py
	README.md
	cba-bot.py
	irc-botmanager.py
	testrun.sh
cbabots: Allow bots to respond to messages

This adds a bunch of new callbacks to allow bots to interact with users.
cbabots: Add gavelmaster auction bot
README: document gavelmaster