RimEnsembleFileSetCollection, RimJobCollection, RimQuickAccessCollection,
RimRefinementRegionCollection and RimFractureTemplateCollection now inherit
from the templated caf::PdmObjectCollection<T> base, reusing the shared
add/insert/delete/items plumbing introduced for RimValveTemplateCollection.
XML field keywords are preserved on every collection so existing project
files continue to load.