Coerce all new-taxon source DOIs to URL form.
Coerce all new-taxon source DOIs to URL form.

This replaces the prior fixes in peyotl. Addresses
https://github.com/OpenTreeOfLife/peyotl/issues/155.

OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree