Add the wonderful stylings and scriptures of one Fazell "@demwunz" Williams
Styling

- simple_form config to add expected classes
- Massage the claimant form to pick up some styles
GDS dates

- Custom simple_form input type for GDS style dates, e.g. f.input as: :gds_date
- As the user can now easily submit arbitrary characters, handle argument error
  from a date failing to parse.
- Update forms and feature specs with GDS style date inputs
Input styling

- Style date inputs per GDS standard
- Style form inputs

Radio styling is broken. Next commit will fix.
Rename GDS date to "know date"

This morning @matharden told me this is the actual name of the pattern.
Fix radio button styling
Merges front-end CSS and adds hints

- Adds and correctly display hint
- Adds hint strings to i18n locale
Merge pull request #1 from ministryofjustice/merge-front-end

WIP: Merging front and back end work streams