Implemented using random words from /usr/share/dict/words.

Thought it would be nice to keep something from the channel for the last
line. Old functionality still applies if the wordlist can't be found.

Fixes #12.
Merge branch 'master' of https://github.com/TCFMark/lackbot.git
Implemented grabbing words from /usr/share/dict/words.

Thought it would be nice to retain some channel-specific context on the
last line. Old functionality still applies if the file can't be found.

Fixes #12.