After saving show a modal containing edited mappings

* After bulk editing, bulk tagging, single mapping edit and bulk adding always return the user to where they were and show a modal window containing their edited selection along with bulk edit tools for making quick fixes
* For non-javascript users the existing flash message remains
* For javascript users a modal shows which gives a confirmation message
  * The modal is dismissed by pressing the "Ok" button
  * Clicking the background on this modal does not close it, preventing accidental dismissal
* Within the modal a table of just-edited mappings are shown, to allow users to check their changes
  * These mappings can be edited again using the bulk-editing technique with checkboxes and buttons

![screen shot 2014-02-24 at 16 13 53](https://f.cloud.github.com/assets/319055/2247430/b3c6e496-9d6e-11e3-9681-3fec4b795162.png)