4.0.0

- NOTE: The v4.x version series only supports Python 3.6 or greater.
  You can keep using fonttools 3.x if you need support for Python 2.
- [py23] Removed all the python2-only code since it is no longer reachable, thus unused;
  only the Python3 symbols were kept, but these are no-op.
  The module is now DEPRECATED and will removed in the future.
- [ttLib] Fixed UnboundLocalError for empty loca/glyph tables (#1680).
  Also, allow the glyf table to be incomplete when dumping to XML (#1681).
- [varLib.models] Fixed KeyError while sorting masters and there are no
  on-axis for a given axis (38a8eb0).
- [cffLib] Make sure glyph names are unique (#1699).
- [feaLib] Fix feature parser to correctly handle octal numbers (#1700).
Release 4.0.0
4 files changed