allow culture cow to provide insight into trello cards it hears about

Summary: adds node-trello and does some comically janky html table munging to create little mini trello cards in hipchat when the culture cow hears a trello url in a message

Test Plan: tested using personal acct

Reviewers: dylan

Reviewed By: dylan

CC: ben, alpert

Differential Revision: http://phabricator.khanacademy.org/D6530