wip: Add rest api

Close #29
Implements #30 

TODO:

- [ ] put the application name in the service .name property
I think it was actually the way it requires `.call` for invocation that threw me off.
```
var method = { soft: 'softStop', hard: 'stop' }[ style ];
assert(method, 'stop style invalid');

current[method](function(status) {
  if (status != null) {
    callback({message: style + ' stopped with status ' + status});
  } else {
    callback({error: 'application not running, so cannot be stopped'});
  }
});
```

I'm fine either way, it's a nit that can be ignored :-)