add object names as API for RTA to radio buttions

Task-number: QTIFW-372

Change-Id: I4b2272d0f7c482bcae2619e46e1ab3df0db77bbc
Reviewed-by: Tarja Sundqvist <tarja.sundqvist@digia.com>
Reviewed-by: Niels Weber <niels.weber@digia.com>