Change-Id: I642056b78570b44fdefe7f0874a8e4c720389f14
(cherry picked from commit d8bb208a85f6366c58426a85b3d4ec1d6e43ac6c)

may be called against a stale connection without the "connect"
event handler having been called, in the case where the pool
attempted to reconnect after being invalidated and failed; the stale
connection would remain present and would be used on a subsequent
attempt.  This issue has a greater impact in the 1.0 series subsequent
to 1.0.2, as it also delivers a blanked-out ``.info`` dictionary to
the event handler; prior to 1.0.2 the ``.info`` dictionary is still
the previous one.
fixes #3497

(cherry picked from commit 4096ad0f0980f6940be57aaee85791df8f975cd7)

(cherry picked from commit 732fb99fc0afbeb69d684b2bfa6d0be6250919a3)

:paramref:`.Pool.reset_on_return` parameter as a synonym for ``None``,
so that string values can be used for all settings, allowing
.ini file utilities like :func:`.engine_from_config` to be usable
without issue.
fixes #3375

(cherry picked from commit c2e3002503242331fc8f2b314e0d4f3c65de9d73)

:meth:`.Connection.invalidate` method, or an invalidation due
to a database disconnect, would fail if the
``isolation_level`` parameter had been used with
:meth:`.Connection.execution_options`; the "finalizer" that resets
the isolation level would be called on the no longer opened connection.
fixes #3302

(cherry picked from commit 068f9a1531c8114360d5fcd964c27fe6a21f4679)

- attempt to add a script to semi-automate the fixing of links

(cherry picked from commit 544e72bcb6af1ca657b1762f105634372eca3bc0)

debug logging message would not emit if the logging were set up using
``logging.setLevel()``, rather than using the ``echo_pool`` flag.
Tests to assert this logging have been added.  This is a
regression that was introduced in 0.9.0.
fixes #3168