Remove data event listener and add startWaitTime option

Hi @ericclemmons

In this code, your grunt task waits for writing console log, `server.stdout.on('data', finished);`.
However, if `console.log("test");` put on top of the express code `server.js`, this code doesn't work well.

like this:

```js
console.log("Express"); // emit data event...
var app = require('./app');

module.exports = app.listen(app.get('port'), function() {
  console.log("Express server listening on port " + app.get('port'));
});
```

So I add an option startWaitTime.

If you accept, please merge it.