==================
- Avoid a KeyError from ``_p_accessed()`` on newly-created objects under
pure-Python: these objects may be assigned to a jar, but not yet added
to its cache. (PR 6)
- Avoid a failure in ``Persistent.__setstate__`` when the state dict
contains exactly two keys. (PR 5)
- Fix a hang in ``picklecache`` invalidation if OIDs are manually passed
out-of-order. (PR 4)
- Add ``PURE_PYTHON`` environment variable support: if set, the C
extensions will not be built, imported, or tested.