remove testhooks support
Define ResultSpec and ListResult
Remove GetParamsCheckMixin and ControlParamsCheckMixin
Change signature for data.get to take ResultSpec args, and no options

This also changes the endpoint test method callGet to take a path rather
than kwargs.
indicate whether an endpoint returns a collection

..and the plural form of a ResourceType
add support for query args in links
factor out string-to-boolean operations
Add getEndpoint method to DataConnector
WIP - rest + jsonrpc

TODO:
 * TODO items
TODO
(WIP) fuzz the REST API

Idea:
  * Generate a lot of URLs, including some filter expressions, but limit
    the total number created per fuzzing run.
  * Use monkey-patching to compare the result of the automatic application
    (ResultSpec.apply) to that of the connector.
  * Do this without pagination, and then apply pagination locally.