setup.py changes:
  Add test and dist_clean commands.
  Add MANIFEST.in file to make sdist command work.
Test changes:
  Remove unneeded runall.py script.  Also, __init__.py.
  Mentioned tests and how to run them in README.

Project to check correctness of system crontab files.  On most
cron implementations these would be the /etc/crontab file and
files in /etc/cron.d