* Update deps
This also updates for the new (and required) paradigm for registering
service implementations as spelled out in
https://github.com/grpc/grpc-go/issues/3385
* Roll back dockertest
It's up to the worker to understand what a change in state means, so
there was no functional difference between simply sending a state change
request and a cancel request.
* Possible api changes.
* Worker API update.
* Updating import alias name.
* Moving session down a level as a member of the GetSessionResponse.
* Marshal the auth flag into the GetSessionResponse proto instead of the session.