Start using Hacking and PyFlakes

Only blacklisting those warnings that are numerous,
so that in principle Hacking and PyFlakes warnings
are tested. Fix the easy ones alongway.

Change-Id: I571f51ebf570ac114509f2dcd71cdce281e7c70a
python3: Introduce py33 to tox.ini

Introduce py33 to tox.ini to make testing with
python3 easier.

Change-Id: I2f339a2ccf113ff14db64c2bbc67a93bd0270962
Signed-off-by: Chuck Short <chuck.short@canonical.com>
Merge "python3: Introduce py33 to tox.ini"