Modifications mostly to allow submission to pypi, few minor adjustments to extend api

* added trove classifiers so package can be submitted to pypi
* added license based on license mentioned in code
* modified directory structure for submission to pypi so that package can
    be installed with pip install strava or easy_install strava
* fixed output in example, data returned in meters per second rather than mph
* updated example to include watts
* added average_watts, maximum_speed, elevation_gain, description, commute
    and trainer properties to ride to match API return
* set up preliminary tests.py

Additional notes:
* might be worth considering requests http://docs.python-requests.org/en/latest/
    for better handling
* considering a helper or stacked object to return mph/kmh or miles/kms. A
    few different ways this can be handled.