Renamed the leftwardLabel and rightwardlabel for Relationship to
leftwardValue and rightwardValue. Renamed the same values for
RelationshipType to leftwardType and rightwardType.
Renamed the columns 'left_label' and 'right_label' in the table
'relationship_type' to 'leftward_label' and 'rightward_label'.
Also renamed all instances of [l|L]eftLabel and [r|R]ightLabel
to [l|L]eftwardLabel and [r|R]ightwardLabel, respectively.