Rewrite REST API functionality

This is intended to simplify REST API management and authentication of messaging using the same parameters that apply to the engine.io protocol. This completely removes all of the old REST API in favor of a simpler workflow.

Additionally, I stopped overriding the the engine.io Socket#send method in favor of an additional method Socket#sendJSON for simplification and straight forward functionality enhancement.

/cc @zendesk/zendesk-radar

### Steps to merge
 - [ ] :+1: of the team

### Risks
 - :warning: **HIGH** This will break existing REST API implementations.