----------------------------
- [varStore] Sort the input todo list with the same sorting key used for the opimizer's output (3767).
- [otData] Fix DeviceTable's ``DeltaValue`` repeat value which caused a crash after importing from XML and then compiling a GPOS containing Device tables (3758).
- [feaLib] Make ``FeatureLibError`` pickleable, so client can e.g. use feaLib to can compile features in parallel with multiprocessing (3762).
- [varLib/gvar] Removed workaround for old, long-fixed macOS bug about composite glyphs with all zero deltas (1381, 1788).
- [Docs] Updated ttLib documentation, beefed up TTFont and TTGlyphSet explanations (3720).