EDIT

ref #6794 change FeatureTree to TermTree

adapt SchemaUpdater to v5.5.1

ref #6794 rename TermVocabulary table to TermCollection and remaining rename FeatureNode -> TermTreeNode

ref #6794 add TermRelation and rename FeatureNode -> TermTreeNode

ref #6794 add TermRelation and TermRelationBase

ref #6794 add term relation type to TermType and fix TermRelationType class

ref #8128 comment changes temporarily to make them compile

ref #6794 add TermRelationshipType

cleanup

preparation for Feature.supportedClasses