Pycrunchbase

* FLexible requests/six versions (35)

* Fix 26 encode url if it has special entities

* Added `profile_image_url` known property to `Organization`, `Person`, and `Product` per CB-5541 bugfix from 2015-10-21
* Added `featured_team` relationship for `Organization` per Crunchbase change on 2016-06-22
* Added known properties `is_current` for `Job` and `is_lead_investor` for `Investment` per CB-9048 on 2016-10-14
* Fixed typos in `addnode.rst`
* Added David Tran to `AUTHORS.rst`

* Alias 'PressReference' to news
* Fix checking for the type of a PageItem, use lowercase compare
* Update test data, those were out of sync with what CrunchBase no returns. Specifically the test data for Fund and Relationship (Organization.past_team)

* Fixed handling null rleationships that api returns
* Update setup.py release alias

* Fixed instructions in usage.rst (20)
* Support nested relationships FundingRound -> Investments -> Organization
* Update README