- add pg8000 version detection for the "sane multi rowcount" feature

now returns lists for ``items()`` and ``values()`` in Py3K.
Early porting to Py3K here had these returning iterators, when
they technically should be "iterable views"..for now, lists are OK.

into more performant executemany() call, similarly to how INSERT
statements can be batched; this will be invoked within flush
to the degree that subsequent UPDATE statements for the
same mapping and table involve the identical columns within the
VALUES clause, as well as that no VALUES-level SQL expressions
are embedded.
- some other inlinings within persistence.py

for an INSERT or UPDATE are now sorted when they contribute towards
the "compiled cache" cache key.   These keys were previously not
deterministically ordered, meaning the same statement could be
cached multiple times on equivalent keys, costing both in terms of
memory as well as performance.
fixes #3165

is being run itself, either from inside the listener or from a
concurrent thread, now raises a RuntimeError, as the collection used is
now an instance of ``colletions.deque()`` and does not support changes
while being iterated.  Previously, a plain Python list was used where
removal from inside the event itself would produce silent failures.
fixes #3163

here and what's just in changelog

:class:`.SynonymProperty` and :class:`.ComparableProperty`.
- The ``info`` parameter has been added as a constructor argument
to all schema constructs including :class:`.MetaData`,
:class:`.Index`, :class:`.ForeignKey`, :class:`.ForeignKeyConstraint`,
:class:`.UniqueConstraint`, :class:`.PrimaryKeyConstraint`,
:class:`.CheckConstraint`.

fixes #2963

:class:`.InspectionAttr`, where in addition to being available
on all :class:`.MapperProperty` objects, it is also now available
on hybrid properties, association proxies, when accessed via
:attr:`.Mapper.all_orm_descriptors`.
fixes #2971