Adopt PEP 8 compliant function name.
Factor-out existing uses cmp_to_key.
Update documentation to use internal pointers instead of external resource.

and improve test coverage.  Thanks Meador Inge for the patch.

requires building pyctype.o into pgen

(memoryviews don't support complex structures right now)

This should fix the test_py3kwarn failure on OS X.  test_support.import_module
also requires this.

Based on a patch by Meador Inge.

 - rename to _test_structmembersType to avoid the class being automatically
   called by test_capi

 - allow space for trailing NUL in inplace_member field of all_structmembers

 - use T_STRING_INPLACE instead of T_INPLACE_STRING as keyword argument
   to _test_structmembersType initializer

 - don't attempt to initialize inplace_member field if T_STRING_INPLACE
   argument wasn't supplied.

 * 'z', 'z#', 'z*' does also accept Unicode
 * unify types name: replace "string or Unicode objet" by "string or Unicode"

Improve clear() method.  Keeps key/value refcnts >= 1 until final dict.clear() so that decrefs to zero won't trigger arbitrary code .  Also runs a bit faster.