Pyramid-urireferencer

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- Better matching on Accept headers (18)
- Nieuwe protected decorator toevoegen die de request niet uit de parent haalt maar rechtstreeks (50)

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- Add some extra logging. (13)
- Add required function :meth:`get_uri` to the :class:`AbstractReferencer` to determine the uri of the current request (7 and 8)

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- Add support for python 3.5
- Some minor doc fixes
- Changed an edge case where `items` or `applications` response attributes could
be `None` so that they are now always empty lists. (6)
- Updated error message and added JSON error message when a backend application can't be reached (9) and when a resource can't be deleted (10)

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- Added module `protected_resources` containing a `protected_operation` decorator function.

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- Added uri and request to references parameters
- Included renderer in request config
- Removed exception in get_references view
- Fixed ApplicationResponse title from json

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- Changed ApplicationResponse.url to service_url.
- Cleaned up some documentation.
- Added an AbstractReferencer that has no implementation whatsoever.
- Added Python Wheel support
- Make sure that the uri parameter is properly urlencoded.