Add appveyor badge (commented). Disable RTD by default.
.. image:: https://img.shields.io/travis/jaraco/skeleton/master.svg
:target: https://travis-ci.org/jaraco/skeleton
-.. image:: https://readthedocs.org/projects/skeleton/badge/?version=latest
- :target: https://skeleton.readthedocs.io/en/latest/?badge=latest
+.. .. image:: https://img.shields.io/appveyor/ci/jaraco/skeleton/master.svg
+.. :target: https://ci.appveyor.com/project/jaraco/skeleton/branch/master
+
+.. .. image:: https://readthedocs.org/projects/skeleton/badge/?version=latest
+.. :target: https://skeleton.readthedocs.io/en/latest/?badge=latest
