Bug 1003788 - [marionette-apps] switchToApp method doesn't wait for the app is rendered on screen.

Wait for transition state of app's frame as opened.

And we remove the async driver support for two reasons:
1. We don't do the async things for marionette tests in Gaia anymore.
2. We don't need to have sync and async version of the workaround at https://github.com/evanxd/marionette-apps/blob/13318c182ba2f1908bed165c1181583a5ba9cd64/lib/launch.js#L28-L43.

http://bugzil.la/1003788