WIP iframe template

Work in progress. To do:

* [x] stub out index_iframe.html
* [ ] create test page?
* [x] documentation

Closes #35

![screen shot 2014-11-05 at 5 26 55 pm](https://cloud.githubusercontent.com/assets/919583/4928344/579c84d0-6543-11e4-8725-580571edbea7.png)