Remove standalone pytest run_tests.py bundle Newer pytest doesn't support generating stand alone testing bundles. Python 3.9 generates errors running the current run_tests.py. Changed doc to use pythonX -m pytest test/ and some light directions on how to install pytest. Thanks to jerrykan for recommendations on how to do the doc updates.

from roundup.dist.command.build import build_message_files, check_manifest
from distutils.command.install_lib import install_lib as base

class install_lib(base):

    def run(self):
        check_manifest()
        build_message_files(self)
        base.run(self)