Remove HipChat room from README
Remove HipChat room from README

I don't think any of us frequent this room any more, so it's probably best not to direct anyone there anymore.
UWFlow/rmc,UWFlow/rmc,UWFlow/rmc,JGulbronson/rmc,JGulbronson/rmc,UWFlow/rmc,JGulbronson/rmc,JGulbronson/rmc,UWFlow/rmc,JGulbronson/rmc