add support for Bitbucket API

[Abhi-khandelwal]

[gene1wood]

@Abhi-khandelwal Thanks for the PR! Any thoughts on why the tests fail for it in Python 2.7?

[Abhi-khandelwal]

@gene1wood , i have no idea why the tests failed for python 2.7, maybe it needs some other dependency.

[slackorama]

Looks like it got rate limited. From the travis job:

E       assert None == 'The Octocat'
E        +  where None = <built-in method get of dict object at 0x7fb948de1e88>('name')
E        +    where <built-in method get of dict object at 0x7fb948de1e88> = {'documentation_url': 'https://developer.github.com/v3/#rate-limiting', 'message': "API rate limit exceeded for 35.227... here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)"}.get```