Streaming Updates for v6

Just getting started but wanted to enumerate the priorities. I'm sure I'm missing a few but here's some things that I think should be on the punchlist:

* [ ] exponential back-off reconnects as defined under [Reconnecting][reconnecting] section of Twitter docs
* [ ] site stream [controls][controls]
* [ ] update and reconnect (see #565)

[reconnecting]: https://dev.twitter.com/streaming/overview/connecting
[controls]: https://dev.twitter.com/streaming/sitestreams/controlstreams