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- support for sessions from Requests, to improve performance when making
several api calls in a row
- provisional support for the new Scim apis
- added a stub for DELETE /users/<userid>, but we are not implementing
this one at the moment
- added a note and a special config key in the test suite only, to skip
tests that create users, since in SaaS Grist they can't really be deleted
- added a note in both the docstring for "GristApi.inspect" and the docs,
to clarify that, in fact, if no reponse is retrieved, then nothing useful
will be left to inspect.