fix #45: fix custom data not actually being deleted on the api server
remove leftover debug statements
Merge pull request #47 from denibertovic/custom_data_delete_fix

fix #45: fix custom data not actually being deleted on the api server
add debug logging to http executor

Comes in handy when we need to trace the exact API calls to the
service.
Resource._sanitize_value(): sanely handle new resources and dicts as values

Note that this might clash with customData, so it's possible we will
have to disallow automatically sanitizing the dict values.
the beginnings of (google, facebook) provider support
Added wrapper for creating provider accounts and check if new

On an Application resource we can call get_provider_account which is
a simple proxy to applications.accounts.create.
Also, added Account.is_new_account to check if the account has been just
copied from the Provider or is it already present in Stormpath.
fix docs build errors
expose Provider class from the resources package
rename provider_id to provider in applications.get_provider_account

Fixed docs as well.
provider_data does not need to be in account's autosaves
Add ability to pass arguments to tox/pytest.

Now we can run a single test from the test suite, or run a single file.
This is useful for debugging when developing.
provider_data should not have writeable attrs
added tests for fetching 3rd party provider data