* added logical defs using output_of for substances
 * NTs: posterior and anterior fornix of vagina
 * split vertebral centrum into cartil. and bony subclasses. Addresses issue #382
 * added image for gastric mucosa
 * cranial nerve fixes
    * made vestibulococ. system parallel division by function: i.e. VC = V+C
    * added taxon constraints for XI and XII
 * phrenic nerve: added relationships
 * new rel: contributes to morphology of
 * NTs: dental plaques and subtypes