Bring new sbt services using the event stream api

removes the old sbt.js apis. Now, you have to use the new Websocket and EventStram API

```js
define(['commons/websocket', 'commons/types'], function(websocket, types){

  var stdout = ko.observableArray([]);
  websocket
    .subscribe({ type: 'sbt', subType: 'LogEvent', event: { entry: { message: String, type: "stdout" } } })
    .each(function(message){
      stdout.push(message);
    });

})
```


https://github.com/typesafehub/activator/blob/196b5a882589e3006a7dac7e4ab48e282d27372b/ui/app/assets/commons/websocket.js#L22-L27

See here, from websocket.