- The :class:`.QueuePool` has been enhanced to not block new connection
attempts when an existing connection attempt is blocking.  Previously,
the production of new connections was serialized within the block
that monitored overflow; the overflow counter is now altered within
it's own critical section outside of the connection process itself.
[ticket:2880]
- restore having the connection closed before decrementing the overflow counter
- A DBAPI that raises an error on ``connect()`` which is not a subclass
of dbapi.Error (such as ``TypeError``, ``NotImplementedError``, etc.)
will propagate the exception unchanged.  Previously,
the error handling specific to the ``connect()`` routine would both
inappropriately run the exception through the dialect's
:meth:`.Dialect.is_disconnect` routine as well as wrap it in
a :class:`sqlalchemy.exc.DBAPIError`.  It is now propagated unchanged
in the same way as occurs within the execute process. [ticket:2881]
- add tests for this in test_parseconnect, but also add tests in test_execute
to ensure the execute() behavior as well
- remove verbiage about "namespaces" from the dogpile example, [ticket:2862]
- fix broken py2k/py3k isms
specify run as module here
- documentation cleanup in ORM including [ticket:2816]