Fix for #102 - Mirror: exited with code 254 signal null

The mirror is now called "shared" and is only ever called once per startup. Jasmine and mocha-web can both use this shared mirror for now. Ideally, each framework should request its own mirror, but I tried that and it was clunky so it needs some more thought!
This will kick off everything whenever the the application's server source changes. We almost want a server session variable that persists across the automatic restarts. Nor sure of the best way to ensure initial=true only once.