Also add an example of constructing a Decimal directly from a float,
update the quickstart tutorial, and tweak another couple of
sentences.

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.