Moved --tag argument and added --container-image
Make use of the new --container-image flag
Set the executor source to something more useful
Allow container_image to be optional when --docker-host is used
Updated readme with new cluster requirements.
Added note about the --docker-host argument
Merge pull request #16 from duedil-ltd/feature/docker-info

Configurable container image
Merge branch 'master' into fix/remove-var-lib-docker

Conflicts:
	portainer/app/scheduler.py