Ability to automatically generate mocks

Being able to automatically generate mocks with a tool like [gomock](https://github.com/golang/mock) would, I think, greatly simplify writing tests.

There are other tools out there, but since gomock is the "official" Go mocking tool, it could make sense to just start using that.

The issue proposes automatically generating mocks with gomock, but names no files, tests, or entry points in neurobot. Start by locating the existing test and interface patterns, then define the integration scope; done should mean mocks are generated consistently and test writing is simpler.

Written by the indexing model from the issue text.