Added validation checking to add a required css class and a * on labels

required: true will be needed on previewable classes or forms which are not
backed by model validtions

Implement validation checking on the method and restyle

Validaiton checking is done in a similar manner to simple_form.

required: true is now only needed on 'previewable' fields
Override validations where field are not required if all blank

HTML5 blocks the form from saving even though these are only required
when all fields are present

Use the id as field names have * if they are required

Fix autocomplete.js

Add in field of operation as a requied field

when label is seperate then we need to specify required: true manually
Fix form builder labels

Only the class of required should be added, this fixes issues with
passing in 'previewable' which breaks the autocomplete
Refactor labeling options and remove HTML5 validation

HMTL5 validations prevent models being saved when they are only
required if all present (attachments for example)
Tidy up whitespace and left over nils on label fields
Fix unit tests

with removed html5 required field
Merge pull request #591 from alphagov/mandatory-fields

Required fields