Adds docker swarm features to the provider for the Docker Engine 17.09.1 and API Version 1.32.
The spec is close to the API. By default, the swarm services are fire and forget. A converging config implements the features of the docker cli to ensure a service and all its replicas are up and running. Furthermore, service can have configs, secrets, networks, mounts and be added to a network.
* Set up test infrastructure with local registry and custom images.
* Updated travis docker version and usage of new test infra.
* Made acc tests constantly output test results.
* Tmp acc test files are ignored.
* Fixed tests with new infra.
* Allowing insecure registries for acc tests. Added fallback for v1 registries.
* Added private image cleanup after tests.
* Refined acc test structure to confirm tf provider standards with make testacc.
