admin.py added !m command and fixed error reporting

A couple of existing commands weren't reporting their errors properly.
That is fixed now.

!m command sets current channel to +m and grants the requestor +o.
Useful for quickly silencing channels.
ircutil: made a log message more useful
Added a README and a TODO

README has a brief intro on the bot, and how to get started running and
developing it.

TODO has a list of ideas that I'd like to get around to at some point.