Python packaging cruft for a NexSON validator tool

This package does not depend on the rest of the
api.opentree... code base. So, it may move at some
point. See README.md for details.
simple script and code for summarizing keys in a NexSON file
Merge branch 'master' of github.com:OpenTreeOfLife/api.opentreeoflife.org
starting simple validator script and testing system
nexson-validator test scripts and documentation of them