* cartilage condensation
  * normalized naming schema - all are cartilage condensation, not -iginous
  * fixed missing develops_froms
weakened equiv aiom - metatarsal precursor patterns need revisited
spinal nerve syns. Comments on thoracic cavity nerve
     * Fixed confusion over cranial foramen vs bone foramen. Introduced new more specific term for former
     * spinal nerve syns. Comments on thoracic cavity nerve
     * cartilage condensation
      * normalized naming schema - all are cartilage condensation, not -iginous
      * fixed missing develops_froms
    * added synonyms
    * nuptial pad relationships and synonyms from wikipedia
    * NTs: left and right thalami
    * NT: peripheral retina. addresses #216
    * NTs: left and right inner canthi
    * NT: intercanthal line
    * added penis spike and bone synonyms
    * obo2owl doesnt handle all URI types very well yet. We should assign proper URIs for all properties anyway. Fixes #214
taxon constraint on epithelium
taxon constraint on epithelium