General tidyings:

* Make sure would_fail_on_url? works not just by coincidence
* Tidy test_mapping
* Whitespace in update_multiple
* Better naming for failed_updates (becomes failures)
* Rename would_fail_on_url? to would_fail_on_new_url?
Reduce number of fields in modal views
Reduce number of fields in modal views, pt 2
Merge pull request #120 from alphagov/view-model-bulk

Tidy the BulkEditor