Split BotConnection into an abstract Connection, and an implementation IrcConnection.

Also:
- Change realname to point to cloudbot.pw
- Fix QUIT messages not being displayed when being killed
- Change conn.cmd(name, [arg1, arg2]) to conn.cmd(name, arg1, arg2)
- Add conn.action and conn.notice for non-irc-specific action/notices
Add profiling plugin for debugging