repairing the model so that we have a proper relationship between task and challenge (requires migration)
pep8ifying
Merge branch 'develop' of github.com:osmlab/maproulette into develop

* 'develop' of github.com:osmlab/maproulette:
  Replacing BSD with Apache license, after getting all contributors to agree by email. Addresses #155
making the get_random_task call less expensive
making the tasks_available function cheaper
have client use the cheaper stats functions, removing deprecated functions, nicer approximate stats wording
stats api call now uses cheaper functions, server name in challenge finished email