Replace chosen with angular-ui-select

Closes #1751

Agg builder now works in Firefox. You can see this by expanding the agg section, and you can test the new functionality by opening the advanced section and choosing some include or exclude flags. Note that the flags won't be part of the query unless you also specify an include/exclude pattern.

`angular-ui-select` doesn't seem to suffer from the same problems as `chosen`. The syntax isn't quite as nice, but it works in FF, and since it's maintained by the angular-ui team, it should be better supported to boot.

**NOTE**: You will need to run `bower install` before testing.