Make Cyphesis load a world on startup

The by far most common scenario for people that want to try out the server is that they start it, but never understand that they need to run cyclient (or currently cyimport). The result is a void world and a confused user.
We should instead by default, when the server is first run, populate it using the cyimport functionality (though we should perhaps do it in-process?).
The cyphesis source tree should contain the world data. A suggestion is to use the "worlds" repository as a subtree.

We need to record that the world has been imported so that we don't do it the next time cyphesis is started.