Refactor IB module a bit. This fixes the asset catalog autotest.

Task-number: QBS-669
Change-Id: I026bc51cd73db64bf8f96163362af4e9b77c70e3
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>