Update auth.TwitterMixin to work with latest version of twitter api.

* Twitter requires use of HTTPS.
* Upon successful auth they redirect to the user's own data endpoint. So we need to followRedirect in the httpclient.
* Needed to up the urls to the latest API version.
* Removed hard coded http://twitter.com url which is some weird legacy from tornado, it's been removed there: https://github.com/tornadoweb/tornado/blob/master/tornado/auth.py#L717

Cheers