Added schedule conflict checking as gate job

Changes about PEP8 and project meta files were pulled from master into the
branch. The code has since then been cleaned up so it now complies with the
Python PEP8 standard.

A simple bash script for cloning the gerrit-powered-agenda was added. This
script will clone the latest master to a cache folder. Files in the cache
folder will be read and compared against the current changes to check for
scheduling conflicts. If conflicts are found, then the job will fail.

Some more hooks for running these jobs might still be required. They will be
followed after once this part looks all good.

Change-Id:  Ia4ab11a7e54af4d8c058a67b5beb8c4f4e0fea9e
Merge "Added schedule conflict checking as gate job"