http://stackoverflow.com/questions/17580649/sqlalchemy-relationships-across-multiple-tables/17583437

with @_legacy_signature, will inspect incoming listener functions
to see if they match an older signature, will wrap into a newer sig
- add an event listen argument named=True, will send all args as
kw args so that event listeners can be written with **kw, any combination
of names
- add a doc system to events that writes out the various calling styles
for a given event, produces deprecation messages automatically.
a little concerned that it's a bit verbose but will look at it up
on RTD for awhile to get a feel.
- change the calling signature for bulk update/delete events - we have
the BulkUD object right there, and there's at least six or seven things
people might want to see, so just send the whole BulkUD in
[ticket:2775]

:meth:`.Insert.from_select`.  Given a list of columns and
a selectable, renders ``INSERT INTO (table) (columns) SELECT ..``.
While this feature is highlighted as part of 0.9 it is also
backported to 0.8.3. [ticket:722]
- The :func:`.update`, :func:`.insert`, and :func:`.delete` constructs
will now interpret ORM entities as FROM clauses to be operated upon,
in the same way that select() already does.  Also in 0.8.3.

when an object we moved from "persistent" to "pending"
using the :func:`.make_transient` function, for operations
involving collection-based backrefs.
[ticket:2773]

checked out count if an existing pooled connection failed to reconnect
after an invalidate or recycle event.  Also in 0.8.3.
[ticket:2772]