Five-intid

---------------------

- When looking for an object by path, treat an AttributeError the same as a
NotFound error. unrestrictedTraverse() raises an AttributeError in certain
cases when it can't traverse.
[optilude]

--------------------

- Install utility in a more permanent manner.
[alecm]

- Drop `five:traversable` statement. It was deprecated since Zope 2.10.
[hannosch]

- Use `objectEventNotify` from zope.component.event instead of zope.app.event.
The later was deprecated since Zope 2.10.
[hannosch]

- Specify package dependencies.
[hannosch]

--------------------

- Fix missing zcml file in prior release

--------------------

- Raise NotYet exception in the default keyreference constructor when the
object does not yet have a proper path. This avoids problems of premature
key references being created and pointing to the parent of the object or
a non-existent object.
[optilude]

--------------------

- Add unreferenceable implementations of intid event handlers and IKeyReference
to deal with IPersistent objects that are never actually persisted, such as
the CMFCore directory view objects.
[mj]

- Remove the explicit exceptions for CMFCore directory view objects and use
subscriber and adapter registrations against unreferenceable instead.
[mj]

--------------------

- Avoid unnecessary adapter lookups in __cmp__ as __cmp__
is called rather often and is performance sensitive.
Cumulative time now 0.080 vs previous 1.820 for 6000 compares
when profiling.
[tesdal]

- Avoid redundant __cmp__ calls in BTree traversal.
[tesdal]