The Cleanup Stuff

Here are commits about the cleanup tasks from rt.cpan.org. No real functionality has changed. I'm going to try to get the functional/documentation changes in tomorrow or Thursday. Never done XS in C before, only C++, so this ought to be interesting.

The Makefile.PL changes are a stopgap until Dist::Zilla or what-not, which can generate that kind of complicated Makefile.PL by itself.
Are these supposed to be in the manifest?  I thought that Makefile.PL always generates them.