PyX 0.13

PyX has been ported to Python 3. It now requires Python 3.2 and above.
Python 2 users should continue to use the previous PyX releases. Along
with the port the text module was modernized and got a new
documentation. In addition, the normpath now removes cusps from
normcurves by spliting the curves on instability points such that
tangents etc. are always well-defined. Various improvements and bug
fixes complete this release.