Require endpoints to be configured.
Add test that only configured endpoints are accepted.
Fix lookup of configured endpoints.
Add endpoint configuration for outbound API tests.
Add setup function for setting up endpoint configs in tests.
Don't require delivery_class when setting up endpoints.
Merge branch 'develop' into feature/issue-147-fail-if-endpoint-not-configured
Merge branch 'feature/issue-147-fail-if-endpoint-not-configured' into develop