Switch to using semantic-ui for table sorting

I've switched to using semantic-ui sortable on the table and allow the user to click anywhere on the header to select a different column to sort by.

![screen shot 2014-11-15 at 16 12 43](https://cloud.githubusercontent.com/assets/60068/5058305/4e9706b6-6ce2-11e4-8540-0b6b30f594c8.png)