v0.7.x

Adds a new `reactor:error` event in order to listen on non fatal errors that occur within the reactors. (e.g when the `redis` module emits an error) as `error` events break the pipe chain. Fixes #59 and #57. 

[`node-backoff`][node-backoff] has been replaced with [`back`][back] in order to fix `node v0.10.x` issues. Fixes #55 and #58.

One issue that still exists is tests not passing appropriately because of [`vows`][vows] but that will be fixed in time.

[vows]: https://github.com/cloudhead/vows
[node-backoff]: https://github.com/MathieuTurcotte/node-backoff
[back]: https://github.com/jcrugzz/back