Redirect to mappings list after single edit

* Caveat: For now itt redirects to the first page of mappings at the
moment, rather than the page you were on before you began editing.
Move mappings table into a partial

* Preparation before using the table in a modal window
Show a modal after editing a single mapping

* Use flash messaging to pass through mapping IDs we can later re-use
* Fix the tag feature which broke in the process (multiple mappings
tables)
  * Create a way of distinguishing between the two and of addressing
exact mappings
Toggle display of mapping table components

* Hide bulk add and footer when showing a modal
Redirect to prior page after editing single

* Return to the context that you left when editing a single mapping
Show modal after bulk editing or tagging
Use smart quotes for tag message
Show modal after bulk adding mappings
Hide the usual success message for js users

* Use the js/non-js style helpers to hide the usual saved success
messages for users that can see modals
Create auto-show-modal JS module

* Move inline JS out of modal include
* Update event listener to use new namespaced Bootstrap 3 event, rather
than the old Bootstrap 2 one
Standardise widths of type and edit columns

* In modal windows with short paths they were growing longer, and the
table looked incorrect
Prevent 'OK' button from wrapping in modal

* Move styles for modal into a separate file
* Remove an ugly inline style
Merge pull request #193 from alphagov/save-modal

After saving show a modal containing edited mappings