(__init__.py still makes format_exception available; is this needed?)

must've used this to disable the exception handling temporarily to
debug the exception formatting machinery, and forgotten to re-enable
it before checking in.

Unfortunately, this made it into the ZODB 3.1 release, making this a
3.1.1 backport candidate.

Fixes #651

Remade the test code for rfc822() to provide more stable tests.

Make TOC items and values sloppier.  These are utility methods used for custom introspection on the TOC.  Under concurrent use, they tended to cause a KeyError
to be raised out of __getitem__ due to a synchronization problem.  Making them more tolerant of desynchronization between _items and _data makes them useful.

Delayed Zope startup based on changes from Zope-2_7-development-branch
(with corrections), with the intent of merging this into the 2_6
branch and the head.

Until now, "import Zope" always opened the database automatically.
Unfortunately, that strategy caused the Python import lock to be held
by the main thread during database initialization, which led to a
deadlock if other threads required something to be imported before
completing initialization.  This can be a big problem for ZEO.

The only foreseen risk is that external scripts which "import Zope"
may depend in some way on the database being opened immediately.  Most
scripts just use "Zope.app()", which still works well.  If you have a
script that breaks with these changes, either add a call to the new
Zope.startup() function or set the ZOPE_COMPATIBLE_STARTUP environment
variable to a non-empty value.

- fixed broken except statement

storage speak, lrevid pointers to shared pickle data in earlier
transactions.

Specifically,

The _Record object now has a data_txn attribute that is either None or
the id of the transaction that contains the data used by the current
record.  Example: When transactionalUndo() modifies an object, it
typical creates a new data record that points at the transaction
before the undo.  The new record contains the same logical data as the
record it refers to.  (For consistency purposes, this is a stronger
claim than that the pickles in two different data records are the
same.)

_Record.__init__(): Gets data_txn passed in from
_RecordIterator.__getitem__(), which in turn getes the lrevid from
Full._loadSerialEx().

_loadSerialEx(): Now returns the backpointer, aka lrevid but only if
it is not the same as the serial argument.  They will always be the
same (and we'll always return None) except in the face of
transactionalUndo, commitVersion, and abortVersion.

input field (collector #117).

- determine the directory containing the supplemental data file in the
  normal way
- don't use assert statements; use the appropriate self.assert*()
  methods consistently
- organize imports in Python Normal Form
- whitespace cleanup

getId.  This is a change designed to make it possible to disambiguate user names and user ids in subclasses of user folders, while still doing the "right thing" with respect to local data structures that keep pointers to user ids (eg. local roles, etc.)

Zope tree every time the DAV Lock Manager control panel is visited, it
gives the user a chance to specify a path to start from, shortening
query times (especially in large databases).

PageTemplateFiles were previously owned by whatever object contained
them.  This resulted in very hard bugs if the user who owned the
container was removed.  Since PageTemplateFiles come from the
filesystem, they are now "unowned", similar to DTMLFiles.  Security is
still applied, but now it is applied correctly.

Ahem, *cough*: "Please run the test suite before checking in a change! At
the very least run the tests for the package you changed."

Date is a required header in RFC822 and RFC2822, so MailHost now adds it if it doesn't exist.

Note that I'm not sure the pids written to the pidfile always make
sense.