* Implement a new package: engine. It exposes a useful but minimalist job API. * Refactor main() to instanciate an Engine instead of a Server directly. * Refactor server.go to register an engine job. This is the smallest possible refactor which can include the new Engine design into master. More gradual refactoring will follow. Upstream-commit: 0d1a825137448e2f41e5aaa5ecae8094c8ab6817 Component: engine