Doc viewer app

This allows users to open and share a link to exactly one document. Closes #717 

![screen shot 2014-12-04 at 4 26 24 pm](https://cloud.githubusercontent.com/assets/1250387/5308264/601368f4-7bd2-11e4-8cd5-d7f533b0e9d3.png)

Q: Why a search here?
A: Elasticsearch GET API doesn't support stored or scripted fields, have to go through the search API

Q: Well then why didn't you use a searchSource?
A: It seemed wasteful to start up a temporary indexPattern and searchSource for one request. I would need to new up an indexPattern as the existing one could match some range of indices, and I need exactly one index. The indexPattern that does get loaded here is only used for formatters and scripted fields retrieval.