pep8 fix (thanks @jerith)
Add helper method to Transport for adding outbound handlers: Transport.add_outbound_handler
Merge branch 'feature/issue-742-add-helper-method-to-transport-for-adding-outbound-handlers' into feature/issue-739-dm-twitter-transport
Fix vas2nets transport tests failing after removing Transport._process_message (these could use the test case's worker helper's dispatch_outbound)
Merge branch 'feature/issue-742-add-helper-method-to-transport-for-adding-outbound-handlers' into feature/issue-739-dm-twitter-transport
Make room for DMs in TwitterTransport
Add support for inbound DMs
Test that we handle endpoints properly in TwitterTransport (and fix things found)
Add support for outbound DMs in TwitterTransport