The upstream (github) tag tarball is used instead of the pypi one, since the
latter omits the test suite and changelog.

The source is repacked to remove:

 * a vendored copy of the PLY library
 * a compressed copy of the yes(1) manpage (used for a test)
 * images and video without source in the documentation
 * .gitignore (since it interferes with git-buildpackage)
