API: Allow adding to a non-literal files list.

Change-Id: I03153c3ace25c28fbd8490a4e054772b3112a867
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
API: Allow adding files to a group with a directory prefix.

This case is not problematic.

Change-Id: I388df6180b231364a8e185eb85aee5adff417965
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>