Porting of the codebase to Python 3.3.5, while maintaining retrocompatibility with Python 2.6/2.7: tests have been worked out to support both versions and PyOWM installation has been tested both with Python 2.x and Python 3.x environments; adapted Travis-CI runner config file accordingly. Removed JSON and XML dump unit tests for model entities as they are too verbose and prone to string pattern order mismatching during assertions. General code cleaning.
Merge branch 'master' of https://github.com/csparpa/pyowm