Update badges to refer to Linux and Appveyor.
.. image:: https://readthedocs.org/projects/cherrypy/badge/?version=latest
:target: http://docs.cherrypy.org/en/latest/?badge=latest
-.. image:: https://img.shields.io/travis/cherrypy/cherrypy/master.svg?label=*NIX%20build%20%40%20Travis%20CI
+.. image:: https://img.shields.io/travis/cherrypy/cherrypy/master.svg?label=Linux%20build%20%40%20Travis%20CI
:target: http://travis-ci.org/cherrypy/cherrypy
-.. image:: https://img.shields.io/appveyor/ci/jaraco/cherrypy/master.svg?label=Windows%20build%20%40%20Travis%20CI
+.. image:: https://img.shields.io/appveyor/ci/jaraco/cherrypy/master.svg?label=Windows%20build%20%40%20Appveyor
:target: https://ci.appveyor.com/project/jaraco/cherrypy/branch/master
.. image:: https://img.shields.io/pypi/pyversions/cherrypy.svg
