minor def change
 * Fixed def of extraembryonic structure to be the same as latest CARO
 * nerve fiber - made disjoint union of myelinated and unmylelinated forms
     * Fixed def of extraembryonic structure to be the same as latest CARO
     * nerve fiber - made disjoint union of myelinated and unmylelinated forms
     * made commissure terminologically and logically appropriate for non-myelin-axon taxa. Fixes issue #325
     * weakened develops_from relationship mouth -> stomodeum to contribution - some parts of tghe mouth are ectodermal. Fixes DV with ZFA
     * jaw refactoring
     * Fixed inverted L/R xrefs for EHDAA2 in auricular muscle tissue. Fixes issue #321
     * Fixed synclash for spinal cord neuromere
     * Added ambiguous_for_taxon.
     * Added not_recommended_for_taxon
     * editing nervous system def and adding to cumbo slim
 * XAO xref for pharyngeal mesenchyme, adapted xao definition for uberon
Merge branch 'master' of github.com:cmungall/uberon
 * Added relations for uvular muscle
 * null changes on comments
taxon notes for uvula