Return bulk edit table via ajax, display in modal

* Put back previously removed jquery_ujs so that ‘remote: true’ works
as expected
* Use javascript hooks to select an input type and submit the edit
multiple form, displaying the resulting HTML in a bootstrap modal window
* When the modal window is hidden remove it from the dom
* Extend selectable table module to include the wrapping form
* Known issues: Submitting the form without anything selected breaks
the modal. There’s no ajax loading indicator or error handling.