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]

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

value is present

mapped class where the polymorphic discriminator has been assigned
to a value that is invalid for the class.   [ticket:2750]

adapter to an aliased-mapped, non-polymorphic selectable that prevented us from referring
directly to that selectable.

passes in AliasedInsp and allows more flexibility.
- rework the AliasedClass/AliasedInsp relationship so that AliasedInsp has
all state and functionality.  AliasedClass is just a facade.
[ticket:2756]

entities against the same base class joined to each other as well
would not track columns on the base table independently of each other if
the string of joins were more than two entities long.  Also in 0.8.2.
[ticket:2759]

would produce a parenthesized expression not accepted by some databases.
[ticket:2754]