Stats panel and stats adhoc facet for table

This pull adds options for the stats panel for each of the supported calculations in the elasticsearch statistical facet
![screen shot 2014-04-22 at 9 39 48 pm](https://cloud.githubusercontent.com/assets/1250387/2773652/821cfcb8-caa1-11e3-8bb7-467b531db807.png)

It also adds a 'stats' button for numerical fields in the table
![screen shot 2014-04-22 at 9 40 03 pm](https://cloud.githubusercontent.com/assets/1250387/2773654/8f97730a-caa1-11e3-9793-44887d9fb80b.png)