Python stacks should ship wheelhoss

A common gotcha in Python packaging is the need to include the source files, which SPK tends to miss. We should go ahead and grab a release of wheelhoss (https://github.com/troyjfarrell/wheelhoss/) in our Python stacks during setup, and then run it on build. It's about a half megabyte built but will save Python packagers a lot of stress looking for what went wrong.