any current storages.

included unless the -L option is provided.

a transaction id to be spacified, rather than being defined
by the storage. This should *only* be used when copying data
from one type of storage to another.

from one storage to another.

than the (timestamp of the first record written after the) last pack.
Packing to a time earlier than the last pack can cause serious data
lossage.

requested disregarded the filter. That is, the arguments first and
last should be applied *after* filtering.

database rather than the mounted database.

attributes are registered.

got registered. (Deja vu all over again. ;)

Changed to commit objects in registration order and to allow
additional objects to get registered while commiting. (The
later was wanted by PJE.)

Added a comment in commit to explain the "invariant".

Fixed bug that caused objects to get multiply aborted.  Now always
clear object registry on commit and abort. This seems like a good
idea anyway. (We were relying on free_transaction to have the
same effect. This faild miserably in single-threaded apps and
in certain error conditions.

Added a teeny optimization in get_transaction().

transparent Pythonic sematics for __setattr__ and __delattr__.
If these methods are implemented, then they *must*::

  self._p_changed=1 # prefered

or::

  self.__changed__(1) # if people get the heebe-jeebees from setting attrs

to manually register that an object's persistent state has changed, if,
in fact, it has.

Fixed "while objects" loop in commit to do the right thing with the object list element (toss it) if it doesn't have a _p_jar.  Not doing this was causing an infinite loop.

Added macro, PERSISTENCE_FLAGS, that contains the standard persistence ExtensionClass class flags. This macro is provided to make it easier to maintain persistent base classes.

with standard Python semantics.