Collections

[carlfeberhard]

This PR allows the user more flexibility and editing power when creating list and pair collections.

For the list creator:

• a modal is opened, any non-valid elements are displayed in a dismissable alert, help is displayed behind it (in the style of the list of pairs creator), and possible elements for the final collection are shown in the center.
• Elements can be dragged and dropped to re-order them.
• Duplicate names are mangled (as OSX ('name (1)') and the user can further click the name to edit it.
• The user can discard any elements they previously selected by clicking a 'Discard' button.
• The user can begin again (as if they just opened the dialog) by clicking 'start over'.
• The final collection name is now editable (and autofocuses on modal startup).

For the pair creator (for the most part, the same as the list creator changes):

• Forward and reverse elements are 'swap'-able instead of dragging to re-order.
• No discarding, 'start over', or renaming (not needed for this simpler collection structure).

[jmchilton]

Had tried this branch out pre-PR - really fantastic stuff @carlfeberhard! 👍

[dannon]

+1