Start a very minor test suite

[Kit Barnes]

At the very least we could have a fake line stream and mimic an IRC session that tests various bits and bobs so I don't have to keep putting the client in #possel-test and then joining from a local irssi session.

Things I usually test manually at the moment:

• It responds correctly to ping
• It joins a channel correctly
• It can send to a channel
• It correctly parses and models when:
  • User joins channel
  • User quits channel
  • User parts channel
  • User changes nick
  • User messages channel