Add Bugzilla integration

I'm not sure what would happen if the user typed wrong, for example, username in the "assigned-to" field. If that happens, Bugzilla returns an error. Also, in some places I `throw` errors. How safe is it?

![screenshot 2014-07-15 21 33 14](https://cloud.githubusercontent.com/assets/1079123/3594643/27d3d788-0ca3-11e4-8a80-223c2955c38b.png)

Depending on the response of the request, doing something like this should work.

```coffeescript
req.end (res) =>
  return callback res.error if res.error
  @getResponse(res, callback)
```

[Superagent](https://github.com/visionmedia/superagent) looks at the status code of the response and figures out whether the request was successful or not (according to the server it hit, or whether it did not hit a server at all).

Of course the same would apply here too...

```coffeescript
req.on 'error', (err) ->
  callback err
```