OGM-521 Fix creation of AssociationKeyMetadata for *ToOne associationtions
OGM-521 Create class AssociateEntityMetadata to store information related to *ToOne associations
OMG-521 Add TupleContext#getAssociatedEntityMetadata

  It provides a way to obtain information about associated entities
  given a column that it is part of a foreign key.
OGM-521 Proper initialization of TupleContext in OgmEntityPersister
OGM-521 Fix compilation erros due to the new constructor in TupleContext
OGM-521 Ignore updates on foreign columns for Neo4j

  Neo4j has relationships so we don't need to store foreign columns in
  the nodes.
OGM-521 Update test mapping *ToOne associations in Neo4j
OGM-521 Update Neo4j javadoc