Log Message:
py-fonttools: update to 4.17.1.

4.17.1 (released 2020-11-16)
----------------------------

- [colorLib] Fixed regression in 4.17.0 when building COLR v0 table; when color
  layers are stored in UFO lib plist, we can't distinguish tuples from lists so
  we need to accept either types (e5439eb9, googlefonts/ufo2ft/issues#426).

4.17.0 (released 2020-11-12)
----------------------------

- [colorLib/otData] Updated to latest draft ``COLR`` v1 spec (#2092).
- [svgLib] Fixed parsing error when arc commands' boolean flags are not separated
  by space or comma (#2094).
- [varLib] Interpret empty non-default glyphs as 'missing', if the default glyph is
  not empty (#2082).
- [feaLib.builder] Only stash lookup location for ``Debg`` if \ 
``Builder.buildLookups_``
  has cooperated (#2065, #2067).
- [varLib] Fixed bug in VarStore optimizer (#2073, #2083).
- [varLib] Add designspace lib key for custom feavar feature tag (#2080).
- Add HashPointPen adapted from psautohint. With this pen, a hash value of a glyph
  can be computed, which can later be used to detect glyph changes (#2005).

4.16.1 (released 2020-10-05)
----------------------------

- [varLib.instancer] Fixed ``TypeError`` exception when instantiating a VF with
  a GSUB table 1.1 in which ``FeatureVariations`` attribute is present but set to
  ``None`` -- indicating that optional ``FeatureVariations`` is missing (#2077).
- [glifLib] Make ``x`` and ``y`` attributes of the ``point`` element required
  even when validation is turned off, and raise a meaningful ``GlifLibError``
  message when that happens (#2075).

4.16.0 (released 2020-09-30)
----------------------------

- [removeOverlaps] Added new module and ``removeOverlaps`` function that merges
  overlapping contours and components in TrueType glyphs. It requires the
  `skia-pathops <https://github.com/fonttools/skia-pathops>`__ module.
  Note that removing overlaps invalidates the TrueType hinting (#2068).
- [varLib.instancer] Added ``--remove-overlaps`` command-line option.
  The ``overlap`` option in ``instantiateVariableFont`` now takes an ``OverlapMode``
  enum: 0: KEEP_AND_DONT_SET_FLAGS, 1: KEEP_AND_SET_FLAGS (default), and 2: REMOVE.
  The latter is equivalent to calling ``removeOverlaps`` on the generated static
  instance. The option continues to accept ``bool`` value for backward compatibility.

4.15.0 (released 2020-09-21)
----------------------------

- [plistlib] Added typing annotations to plistlib module. Set up mypy static
  typechecker to run automatically on CI (#2061).
- [ttLib] Implement private ``Debg`` table, a reverse-DNS namespaced JSON dict.
- [feaLib] Optionally add an entry into the ``Debg`` table with the original
  lookup name (if any), feature name / script / language combination (if any),
  and original source filename and line location. Annotate the ttx output for
  a lookup with the information from the Debg table (#2052).
- [sfnt] Disabled checksum checking by default in ``SFNTReader`` (#2058).
- [Docs] Document ``mtiLib`` module (#2027).
- [varLib.interpolatable] Added checks for contour node count and operation type
  of each node (#2054).
- [ttLib] Added API to register custom table packer/unpacker classes (#2055).