Add routing metadata and helpers to TransportMessage.
Initial endpoints implementation with transport and application base classes using it.
Better back-compat in app setup.
Simplify endpoint assignment on published messages.
Compat fix.
More compat improvements.
Extract common functionality from Transport and ApplicationWorker.
Merge branch 'develop' into feature/issue-457-endpoints-and-connectors

Conflicts:
	vumi/application/base.py
	vumi/transports/base.py
New connector/endpoint-based dispatcher base and RoutingTableDispatcher.
Merge branch 'develop' into feature/issue-457-endpoints-and-connectors
Default amqp_prefetch_count to 20 for all BaseWorkers.
Always return a deferred from _setup_unpause().
Warnings are already only emitted once.
Remove unused import.
Merge branch 'feature/issue-457-endpoints-and-connectors' of github.com:praekelt/vumi into feature/issue-457-endpoints-and-connectors
Merge branch 'develop' into feature/issue-457-endpoints-and-connectors

Conflicts:
	vumi/transports/integrat/tests/test_integrat.py
Clean up some test helpers.
Rename all the non-endpoint things that were called endpoints.
Rename vumi.endpoints to vumi.connectors since it contains connectors rather than endpoints.
Rename BaseWorker._connectors to BaseWorker.connectors and make it part of the public API of BaseWorker.