Coded method purge() of class Cycle.
Rearranged default options and the default section is now lowercase.
Added Controller.run() method, tests, and bug fixes.

The DEFAULTS had the key sources corrected to sourcedirs.
The hosts command line argument is now saved to the hosts variable
rather than host (without s).
Debug messages were added in config.py.
The Controller class now has a run method. This allows unit tests to
check or alter configuration before anything happens.
Added dummy hosts in the test configfile.