Rename IRC-FMT to BOT-MESSAGE and add BOT-COMMENT

Functions BOT-MESSAGE and BOT-COMMENT are used to format string for
bot's output. Currently the latter adds ";; " prefix.
Reformat lines so that they are shorter than 80 characters
Convert README to markdown (.org -> .md)
Update copyright years: 2012-2013
Use Quicklisp to load our own files too