[cairo] Python Wrapper For Pixman

[Lawrence D'Oliveiro]

python_pixman <https://github.com/ldo/python_pixman> is a high-level
wrapper for the Pixman pixel-manipulation library. I wanted to do some
effects, like blur, which Cairo doesn’t support. But since Cairo itself
makes use of Pixman, I thought I would do the same.

This builds on top of Qahirah, my Python wrapper for Cairo itself. I
haven’t done Pixman’s transformations yet: I don’t want to duplicate
all the functionality of the Matrix and Vector types I already did for
Qahirah. I have already used subclassing of Qahirah’s Vector and Rect
types to save some duplication.

At some point I intend to publish some examples of python_pixman in use.