support oauth tokens

[rgarcia]

breaks clever.api_key = "..."

[mohit]

Does anyone mind if I experiment with doing this using a more pythonic way. I think the behavior to run the same tests in different conditions is possible by using a different test loader and then passing it instances of the class, rather than creating seperate classes for each.

[rgarcia]

yeah I struggled with changing this test file, so please experiment!

[nathanleiby]

@rgarcia can we necromance this PR?

Also, if you don't want to break clever.api_key backwards compatibility, you could make that an alias for ~ "if auth not set then set_api_key else throw exception". But I think it's better to remove it and update the package version appropriately.

[rgarcia]

@nathanleiby sounds good, I'll merge and publish a major version bump shortly