README Documentation

Documentation for the following:

 - [x] Connecting to the bus
 - [x] Publishers
 - [x] Subscriptions
 - [ ] Request/response
 - [ ] Publisher confirms
 - [ ] Consumers
 - [ ] Integrating with DI
 - [ ] Integrating with Loggers
 - [ ] Custom serializers
 - [ ] Extending the bus
 - [x] Multiple endpoints (for priority)
 - [ ] Timeouts/deadletter
 - [ ] Using rest api