The poll breakdown modal replaces the grouped pie charts feature.
Includes:
* MODAL: Untangle `onSelectPanel`
Previously modal-tab component would call on click the onSelectPanel callback with itself (modal-tab) as `this` which severely limited its usefulness. Now showModal binds the callback to its controller.
"The PR includes a fix/change to d-modal (b7f6ec6) that hasn't been extracted to a separate PR because it's not currently possible to test a change like this in abstract, i.e. with dynamically created controllers/components in tests. The percentage/count toggle test for the poll breakdown feature is essentially a test for that d-modal modification."
- add User.staff scope
- inject MessageBus into Ember views (so it can be used by the poll plugin)
- REFACTOR: use more accurate is_first_post? method instead of post_number == 1
- FEATURE: add support for JSON-typed custom fields
- FEATURE: allow plugins to add validation
- FEATURE: add post_custom_fields to PostSerializer
- FEATURE: allow plugins to whitelist post_custom_fields
- FIX: don't bump when post did not save successfully
- FEATURE: polls are supported in any post
- FEATURE: allow for multiple polls in the same post
- FEATURE: multiple choice polls
- FEATURE: rating polls
- FEATURE: new dialect allowing users to preview polls in the composer
