Object (component) string id not accessible by users

Currently, string id's for components are not accessible through the public api and we have had lots of requests of users of our gui automation tool (tdriver) wanting to access object string id's of qml applications.

I have attached a merge request with a patch that will add an api method to access the string id's of objects on given their context:
https://qt.gitorious.org/qt/qt/merge_requests/2592