Impletments new method to check/get the name of a primary field. Returns false when no such field exists in container.
Impletments new method to check/get the name of a primary field. Returns
false when no such field exists in container.

Signed-off-by: Michael "Tekkla" Zorn <50f195679bf77bf0955b9c2832e55e1d0c47d29c@tekkla.de>
tekkla/TekFW,tekkla/TekFW