Eventbrite: Remove widget used only by the Venue theme.
Eventbrite: Correct typo in comments.
Eventbrite: Update token meta for the Eventbrite API v3.
Eventbrite: Set endpoint constant to new v3 API.
Eventbrite: Update to v3 of the Eventbrite API.

* Entirely possible some of it is broken.
* Removes any references to "occurrence", the old way of handling recurring events. When implemented (expected July 2014), the new API will treat recurring events as full, proper events, grouped together (possibly with `parent_series`).
Eventbrite: Use local time rather than UTC.
Remove unnecessary hook.
Fix missing checkboxes for featured events in the admin listings.