Make hubot-hipchat self hosting

For some reason, I need this module `hubot-hipchat` to be self hosting, i.e dont assumed that it always installed alone side with a `hubot` module.

So I made `hubot` as the dependency of `hubot-hipchat`, make it no longer relied on that assumption.

During the testing, I had an error said that it missing package `async`, so I add that package as well. If I am wrong on this , please correct me.