value is present

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

you're dealing with aliased() or with_polymorphic() you need to say "flat=True".  Just the one
flag though, "flat" implies "aliased".

- went through examples/ and cleaned out excess list() calls

the creation of strong references within the Session;
an object will no longer have an internal reference cycle
created if it's in the transient state or moves into the
detached state - the strong ref is created only when the
object is attached to a Session and is removed when the
object is detached.  This makes it somewhat safer for an
object to have a `__del__()` method, even though this is
not recommended, as relationships with backrefs produce
cycles too.  A warning has been added when a class with
a `__del__()` method is mapped.
[ticket:2708]

query when refreshing an inheritance-mapped class
where the superclass was mapped to a non-Table
object, like a custom join() or a select(),
running a query that assumed a hierarchy that's
mapped to individual Table-per-class.
[ticket:2697]

  subclass could insert the row for the "sub" table
  before the parent table, if the two tables had no
  ForeignKey constraints set up between them.
  Also in 0.7.11. [ticket:2689]
- fix a glitch in the assertsql.CompiledSQL fixture regarding
when a multiparam compiledSQL is used within an AllOf
- add a new utility function randomize_unitofwork() which
does the function of --reversetop

- other cleanup
- don't need compat.decimal, that approach never panned out. hopefully
outside libs aren't pulling it in, they shouldn't be