[Distutils] Some patches

I have put a few patches up on the SourceForge patch manager.

The first patch prunes CVS files and directories from source distributions. (Making a source distribution of the Distutils was failing because it kept putting 'misc/CVS' into MANIFEST. Of course, this wouldn't effect somebody who wasn't using the CVS Distutils.)

The second patch fixes a problem that you could not build source distributions for packages that use the old-style way of specifying extensions.

The third patch is for the examples directory. It updates the pil and xml setup scripts to use new-style extensions and fixes a bug in the mxDateTime setup script (which uses new-style extensions but did not import the Extension class.)