checking for tree and tree id uniqueness in conversion
Authors file merged with Contributors. License authors fixed
Relaxing CC0 requirement when adding new studies.
Merge branch 'master' of github.com:OpenTreeOfLife/peyotl
AUTHORS replaced by CONTRIBUTORS
Merge branch 'master' of github.com:OpenTreeOfLife/peyotl
Fix misplaced ^ot:license element in new nexson.
Merge branch 'master' of github.com:OpenTreeOfLife/peyotl
merged
minor