Don’t redirect to dataset url on unpublished result as that 404’s

It probably shouldn’t do that but that’s a different issue
Be explicit about wanting the newest ResponseSet
If dataset already exists don’t duplicate it.

Build new response sets and certificates on same dataset record
Don’t send confirmation email when user is created.

We’ll want a more appropriate email to be sent out.
Only build response set if necessary

It may already exist if certificate is being updated
Duplicate assumptions about DGU to London Datastore
Merge pull request #979 from theodi/feature-update-certificate-api

Merge this in now so I can run the London Data Store import.