Issue #16922: fixed findtext() to return empty Unicode string instead of empty bytes object when there's no text.

Patch by Serhiy Storchaka.

Issue #16922: fixed findtext() to return empty Unicode string instead of empty bytes object when there's no text.

Patch by Serhiy Storchaka.

Coverity report) and cleanup code.

Thanks to Ezio Melotti and Daniel Shahaf for the patch.

Patch by Serhiy Storchaka

with the Python version of the class.

Patch by Daniel Shahaf.

In conformance with the documentation and the Python version.
Patch by Franck Michea.

Issue #16089: Allow ElementTree.TreeBuilder to work again with a non-Element element_factory (fixes a regression in SimpleTAL).

Issue #15144: Fix possible integer overflow when handling pointers as integer values, by using Py_uintptr_t instead of size_t.
Patch by Serhiy Storchaka.

ISsue #14988: restore Python 2's behavior of raising ImportError when unable to load pyexpat, instead of a SystemError/RuntimeError

Replace the iter/itertext methods of Element in _elementtree with true C implementations, instead of the bootstrapped Python code. In addition to being cleaner (removing the last remains of the bootstrapping code in _elementtree), this gives a 10x performance boost for iter() on large documents.
Also reorganized the tests a bit to be more robust.

Includes exposing a doctype handler from expat through pyexpat.

the code are unnecessary.

_elementtree, with a test.

Add attrib keyword to Element and SubElement in _elementtree.
Patch developed with Ezio Melotti.

* Fixed refleak problems when GC collection is run (see messages in
  issue #14065)
* Added weakref support to Element objects

append, extend and insert now consistently type-check their argument in both
the C and Python implementations, and raise TypeError for non-Element
argument.

Added tests

consistent to the one raised by the Python module (the 'code' attribute
was added).

In addition, the exception is now documented.

Added a test to check that ParseError has the required attributes, and
threw away the equivalent doctest which is no longer required.

Fixed the problem and added some tests. Closes #14178

This makes the C implementation more aligned with the Python implementation.
Also added some tests to ensure that Element is now a type and that it can
be subclassed.

Issue #13988: cElementTree is deprecated and the _elementtree accelerator is automatically used whenever available.

Issue #13988: move the python bootstrap code to cElementTree.py, and remove obsolete code for Python 2.4 and 2.5.

Closes #7334: close source files on ElementTree.parse and iterparse (partial backport of issue #10093 from 3.2).