Adding remote control dependency

I was getting this stack trace trying to run the example.

```
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Ratpack.groovy: 5: unable to resolve class ratpack.remote.RemoteControlModule
 @ line 5, column 1.
   import ratpack.remote.RemoteControlModule
   ^

1 error
```

![image](https://cloud.githubusercontent.com/assets/1033018/3399027/5143356c-fd37-11e3-8892-a2dbe6b018a0.png)