* General test improvements.
* Adjust tests to older docker-py versions.
* docker_swarm_server_info: work around problems with older docker-py versions
* Bump minimal docker-py version for options network_filters and disk_usage.
* More general test improvements.
* Correct usage of docker_image.
* Put files into output directory.
* Speed up test.
* Remove old check.
* Check minimal API and docker-py versions for all docker_* tests.
* Improve docker_swarm creation/destruction for tests.
* Fail when conditions aren't met.
* Don't hardcode address for advertise_addr.
