updated hipchat service to have quiet comments and labels

This is a patch for issue #902 trying to make the hipchat integration a lot less verbose.
We tried moving to their new add-on but it was even more verbose...

This is my first time working with github-services so feel free to point anything out that I have missed.
I wasn't clear if I needed to do anything else to get the options appearing in the control panel on github itself apart from add them to the hipchat.rb file
Not trying to be a pain, but can you also check that the event is `issue` or `pull_request`? Just in case in the future we add a "label" or "assign" action to a different event. :cake:

Something like `return if event.to_s =~ /issue|pull_request/ && payload['action'].to_s =~ /label/ && data['quiet_labels']` should work. It's certainly not pretty but...