Tempstorage

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- Drop Python 3.3 compatibility, add Python 3.6 compatibility.

- Require ZODB 5.0 or newer.

- Use `storage._lock` as a context manager.

- Declare PyPy compatibility.

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- Python 3.3-3.5 compatibility.

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- Explicitly state distribution dependencies instead of re-using the
ZODB test requirements.

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- Disabled ``check_tid_ordering_w_commit`` test from BasicStorage, as it uses
invalid test data.

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- Require at least ZODB 3.9 and adjusted method signatures to disuse versions.

- Expanded dependency on ZODB3 to include the test extra.

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- Approximate PEP8 compliance.

- Split out the ZODB protocol tests from the tests specific to the module.
Make the local tests use "normal" unittest conventions.

- Comply with repository policy.

- Clean imports, docstrings; add an instance-level hook for GC parms.

- Fix a test failure due to never-unghostified root in second connection.