Glyphslib

- Correctly handle preferredFamilyName, preferredSubFamilyName and other instance properties that used to be stored in custom parameters in v2 (881, 884, 885).
- [smart_components] reverse direction of flipped smart components (883).

Newly added support for:

- Smart components (822, 829, 840)
- Glyphs 3 alternate layers (828, 833, 834, 839, 842)
- Corner components (831)
- Rename Glyphs custom parameter (832)
- Right-to-left kerning in Glyphs 3 (865)
- Saving postscript hinting information to UFO (825)

Fixes:

- Fix interaction between COLRv0 layers and components (875)
- Look in the "Axis Location" custom parameter for axis mappings (810)
- Preserve custom name table entries when roundtripping to UFO. (827)
- Maintain instance properties when saving (862, 864)
- Don't use "default" feature writers when the user has provided their own `kern` feature (849)
- Maintain the "postscriptFontName" in Glyphs format v3 files (878)

Smaller improvements:

- use fontTools.misc.transform instead of glyphsLib.affine (854)
- Reduce the ordering difference with respect to Glyphs (863)
- Add option to expand_includes in features (798)
- Use version 3 structures internally (869, 874)
- Improvements to custom name table entries (871, 872, 857, 858)
- Improvements to the support for the "Variable" instance (815, 819, 856)

**Full Changelog**: https://github.com/googlefonts/glyphsLib/compare/v6.1.0...v6.2.0

- Support for loading .glyphspackage sources (803).
- Support converting "meta Table" custom parameter to UFO 'public.openTypeMeta' (808).
- Parse GSInstance.type attribute for Glyphs3 sources, and ignore instances marked as 'variable' when building DS axis mappings (812).
- Write out master names when saving a Glyphs2 source as format 3, previously they were incorrectly reset to 'Regular' (811).

- Implement the "Feature for Feature Variations" custom feature (796)
- Write GDEF categories for glyphs to the UFO public.openTypeCategories lib key (792)

- Make the first point of an open contour behave the same with regards to the 'name' attribute as following points (789).
- When building COLRv1 layers, avoid creating color glyphs with empty PaintColrLayers list.

- Ensure instance width class is remapped to user-space values in Glyphs 3 sources (780, 781).
- While importing UFO features.fea to Glyphs, handle the case where a mark class is used as the value for a glyph class (694, 682).
- Fixed regression whereby the advance width of intermediate layers was being overwritten by the width of the associated master layer (773, 774, 777).