ImageSetUpdater script does not update inherited image variants

ImageSetUpdater is part of essentials plugin gallery manager, but also this script is used by older implementation projects to update image variants. Suppose image set is appended with new image variant while already in use, so existing images need to be updated with the new variant.

Currently ImageSetUpdator can update ONLY variants that are defined with each imageset explicitely. So direct children of:

/hippo:namespaces/uva/myimageset/hipposysedit:nodetype/hipposysedit:nodetype

Suppose, default image is extended by yet another imageset, say "bannerimageset". Because "bannerimageset" inherits from "myimageset" inherited variants are missing here:  

/hippo:namespaces/uva/bannerimageset/hipposysedit:nodetype/hipposysedit:nodetype

So, it would be an improvement to current script to update also inherited variants. Not just directly available variants. Currently to work around this, defined image variants need to be duplicated, which is not clean.