Add toggle auto refresh

related to issue #811.

Enable auto refresh:

![screenshot from 2014-12-03 17 42 35](https://cloud.githubusercontent.com/assets/700876/5277696/ca21ae8c-7b13-11e4-81cc-f46571149cdf.png)

Disable auto refresh:

![screenshot from 2014-12-03 17 43 37](https://cloud.githubusercontent.com/assets/700876/5277709/ef51734a-7b13-11e4-8271-058ce06ab9de.png)