Added functionality to BotUtils; enhanced admin commands; added additional configuration options.

* It is now possible to specify the command prefix in botrick.conf as
well as the reconnection frequency, the number of reconnection attempts,
and whether or not the bot should attempt to rejoin a channel if kicked.
* The bot now autorejoins a channel after being kicked (if permitted by
the settings in botrick.conf)
* Calling of update() from within the module subthreads has now been
fixed--update() will now run constantly.
* It is no longer possible to authenticate twice as a trusted user.
* Added support to BotUtils so that Python scripts may obtain and set
the current nickname of the bot, join channels, and part channels.