Generate form attribute key on save
Fix jshint error
Move jquery.ui to bower
Fix attributes Unit tests

- Keys will now drop underscore due to use of URL::title. Swap for dash in
  test data
- Empty keys now pass validation (auto generated instead) so drop 'missing key' test
- Remove 'file' input type from 2.x import form
- Remove underscore from fieldnames in 2.x import form
Better showing/hiding of form field editor

- Reset the form attribute editor data when showing/hiding the form
- Pass the attribute default value to its preview
Don't re-render attribute items until the attribute actually saves
Make default/previews options a callback so its up to date with model changes
Back to text area for select/radio options, and build forms on demand