Start working on YouTube link handling

Start working on handling YouTube links correctly.
Minor changes

Make the dispatch function for handle-privmsg use the passed in
nickname, rather than referencing the global variable directly.
Added dependency on clj-time

We need clj-time to parse YouTube durations.
Added duration parsing

YouTube videos now have their durations displayed.
Merge branch 'youtube-links' of github.com:quanticle/clojure-irc into youtube-links

Conflicts:
	src/clojure_irc_bot/indirect_commands.clj
Cleaned up YouTube link handling

Refactored YouTube link handling into two regular expressions to be more
robust against poorly formed YouTube links.