Log Message:
py-fonttools: update to 3.17.0

3.17.0:
- [svgPathPen] Added an ``SVGPathPen`` that translates segment pen commands
  into SVG path descriptions. Copied from Tal Leming's ``ufo2svg.svgPathPen``
  https://github.com/typesupply/ufo2svg/blob/d69f992/Lib/ufo2svg/svgPathPen.py
- [reverseContourPen] Added ``ReverseContourPen``, a filter pen that draws
  contours with the winding direction reversed, while keeping the starting
  point.
- [filterPen] Added ``ContourFilterPen`` to manipulate contours as a whole
  rather than segment by segment.
- [arrayTools] Added ``Vector`` class to apply math operations on an array
  of numbers, and ``pairwise`` function to loop over pairs of items in an
  iterable.
- [varLib] Added support for building and interpolation of ``cvar`` table