Add an easy script to build and run the Docker instance. Update some out-of-date information in the README. Add goose to the Docker image. Remove unnecessary go install step from Dockerfile. Allow dns-test-srv to return a hardcoded address other than localhost. This was preventing a Dockerized Boulder from answering requests from a letsencrypt client on the host. Change allowLoopbackAddresses to allowRestrictedAddresses and make it cover all the private IPv4 ranges. The host IP in Docker is commonly in the 172.* range. Fix a couple of references to lets-encrypt-preview. This was inspired by investigation into https://github.com/letsencrypt/boulder/issues/756. To try and reproduce, I tried running Boulder inside a container, and found some broken things.  | 
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| main.go | ||