in callcounts specific to the "expiration" of objects, as in
the "auto expire" feature of :meth:`.Session.commit` and
for :meth:`.Session.expire_all`, as well as in the "cleanup" step
which occurs when object states are garbage collected.
fixes #3307

any speed improvements :(.   code is in a much better place to be run into
C, however
- The ``proc()`` callable passed to the ``create_row_processor()``
method of custom :class:`.Bundle` classes now accepts only a single
"row" argument.
- Deprecated event hooks removed:  ``populate_instance``,
``create_instance``, ``translate_row``, ``append_result``
- the getter() idea is somewhat restored; see ref #3175

sqlalchemy/orm, sqlalchemy/event, sqlalchemy/testing

to get all flake8 passing