Major restructuring to fix a number of bugs:

  - Methods (retrieved as attributes) were sometimes not
    bound to objects in the right context. This could cause
    acquisition to fail within the methods.

  - An optimization skipped calling the __of__ method, assuming that
    it was skipping the standard acquistion __of__ method. This could
    cause application __of__ methods to get skipped. Now the __of__
    method is never skipped. The return value is inspected to
    see if it can be simplified. In the future we might be willing
    to skip calling __of__ if we *know* that we are skipping a known
    __of__.

  - The special value, Acquired, used to force acquisition
    was not handled correctly when it was acquired from a container.

  - Some error handling was not done quite correctly. I don't know
    if this caused any problems.

  - Nested explicit acquisition wrappers may not have been handled
    correctly when accessed through attribute access of a containing
    implicit wrapper.

Reduced code by sending all searches through the same routine,
Wrapper_findattr.

Added two new features:

  - You can now assign the aq_parent attribute of a wrapper.
    This is deemed to be useful in certain applications, including
    XML/DOM.

  - The method aq_acquire hysterically has two usages:

    o To explicitly acquire from an Explicit acquirer wrapper.

    o To apply a filter to guide the search process (e.g. for security).

    Sometimes, someone might want to apply a filter without forcing
    explict acquisition. An additional optional argument was added
    to allow use of a filter without forcing explicit acquisition.