Merge pull request #64 from moneyadviceservice/use-named-colours

Use named colours and purge close-matching colours
Add SelectSubmitter JS component

This component attaches to the change event on a form
element and submits the form automatically.
snippets
Start integration of snippets into UI
Adds basic snippet UI integration

Includes all snippets partials.
upgrade to next version of comfy
seeding categories shouldn't be rescued
remove unnecessary code
Merge pull request #65 from moneyadviceservice/categories-bugs

Categories bugs
Update Popover method naming
Add snippets dropdown menu and enable more snippets
Close menu on snippet insert
Restrict width of toolbar dropdown menu
Improve hover and active state of toolbar buttons
Bump mas-cms-editor version

Includes enabled line breaks in marked
Add new line below each snippet
Vertically align toolbar buttons
Only allow snippets to be inserted within on a new line

i.e. within an empty <p> tag on a new line
Add disabled state to .menu component
Fix error where opening snippets menu then clicking into editor

Caused by `document` being returned as the `parentElement` of the
current node.