Create an Eventbrite loop.

Eventbrite_Query and Eventbrite_Post are just stripped down versions of WP_Query and WP_post, respectively. This allows developers to interact with Eventbrite events using familiar template tags and query vocabulary. This first pass does not include query vars, and returns just ten events from the API response (all Eventbrite REST API calls return up to fifty events).
Define Eventbrite_Query by extending WP_Query, rather than just copying it.