add "quips" to callin page, harvested from chat

Any message starting with "quip:" will be displayed in rotation on the callin page.  The callin page allows an operator to advance to the next quip, optionally deleting the current one.

Fixes #133 

(Should the chat harvesting happen in hubot?  I can't get it to run locally, so I put it directly in `newMessage`, but it feels a bit hacky there)