Populate a data structure that keeps meta-information actually used for the nodes supplied.
 Cares about meta-model source alternatives, and consults 
MetaModelInfoProvider for actual
 meta-model information necessary for current persistence session.
 XXX in fact, ConceptInfo and other are pretty much what we keep in MetaModelInfoProvider. Perhaps, better code would emerge
 if there is hierarchy of ConceptInfo, PropertyInfo plus two distinct mechanism to fill it: one for regular use, with ConceptDescriptors and alike,
 and second for ant/merge, which populates exactly same structure but from information extracted from other models.