Update govuk_frontend_toolkit to 1.5.0
Copy govuk_frontend_toolkit js from node module

- Update Gruntfile.js to copy files from the govuk_frontend_toolkit npm
to govuk/public/javascripts/
- Update scripts include to link to new JavaScript for radio buttons
and checkboxes
Use GOVUK.selectionButtons

- Update application js
https://github.com/alphagov/govuk_frontend_toolkit#selection-buttons
- Rename to form-chunky-labels partial to form-block-labels to follow
classnames
Add example page for radio buttons and checkboxes
Add JS to show additional hidden content

- Remove .toggle-content, replace with generic .js-hidden
- Add JavaScript to show hidden content associated with radios and
checkboxes
- Fix show/hide not working correctly for National Insurance number
example
Add aria-expanded and aria-controls

- Update example page to display hidden content for both radios and
checkboxes
- Add aria-expanded and aria-controls attributes
Remove console.log
Set aria-expanded and aria-hidden attributes

- Update example text
Set aria attributes

- Set aria-controls on the controlling radio or checkbox
- Update aria-hidden and aria-expanded attributes as content is toggled
- Move to new functions for showing and hiding toggled content
Update govuk_frontend_toolkit to 1.5.0
Copy govuk_frontend_toolkit js from node module

- Update Gruntfile.js to copy files from the govuk_frontend_toolkit npm
to govuk/public/javascripts/
- Update scripts include to link to new JavaScript for radio buttons
and checkboxes
Use GOVUK.selectionButtons

- Update application js
https://github.com/alphagov/govuk_frontend_toolkit#selection-buttons
- Rename to form-chunky-labels partial to form-block-labels to follow
classnames
Add example page for radio buttons and checkboxes
Add JS to show additional hidden content

- Remove .toggle-content, replace with generic .js-hidden
- Add JavaScript to show hidden content associated with radios and
checkboxes
- Fix show/hide not working correctly for National Insurance number
example
Add aria-expanded and aria-controls

- Update example page to display hidden content for both radios and
checkboxes
- Add aria-expanded and aria-controls attributes
Remove console.log
Set aria-expanded and aria-hidden attributes

- Update example text
Set aria attributes

- Set aria-controls on the controlling radio or checkbox
- Update aria-hidden and aria-expanded attributes as content is toggled
- Move to new functions for showing and hiding toggled content
Merge  with master.
Update check to see if dataTarget is undefined

- Improve readability, as typeof undefined will always result in the
string 'undefined'