to function for a many-to-one relationship.  The loader used an
API to place "None" into the dictionary which no longer actually
writes a value; this is a side effect of :ticket:`3061`.
- remove InstanceState._initialize() totally, it's used nowhere
else and no longer does what it says it does
- fill in fowards-port version ids throughout the changes for 1.0.9

to transient objects with attributes unset would leak NEVER_SET,
and negated_contains_or_equals would do so for any transient
object as the comparison used only the committed value.
Repaired the NEVER_SET cases, fixes #3371, and also made
negated_contains_or_equals() use state_attr_by_column() just
like a non-negated comparison, fixes #3374

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

size of the many per-column objects we're hitting, but somehow the overall memory is
hardly being reduced at all in initial testing

and :meth:`.AttributeEvents.dispose_collection`, which track when
a collection is first associated with an instance and when it is
replaced.  These handlers supersede the :meth:`.collection.linker`
annotation. The old hook remains supported through an event adapter.

sqlalchemy/orm, sqlalchemy/event, sqlalchemy/testing

to get all flake8 passing