Add HipChat icons to build notifications

Like it says on the tin. These should also be "backwards compatible" if you will... they should still make sense to IRC users, or those who can only see text for whatever reason.

* Add emoticons for build notifications (including downstream ones):
   * Green tick: success
   * Red exclamation: failure
   * Red line: not being built (deleted branch or no permissions)
   * Green dot: other (will also show the actual status)
* Show "branch" emoticon next to branch name (when not master)
* Reduce build time to 2 decimal places (I medically need this)