should reverse path direction when going cu2qu

[anthrotype]

by default fontmake (via ufo2ft and cu2qu) reverses the glyph contours' winding direction when building TrueType glyf outlines, assuming that sources contain PostScript-style cubic beziers that OT spec recommends to be set in counter-clockwise order.
If that is true (we don't actually validate that), then the resulting TrueType glyf outlines after the flipping become clockwise, which is what the TrueType spec in turn recommends.

https://github.com/googlefonts/ufo2ft/blob/fca66fe3ea1ea88ffb36f8264b21ce042d3afd05/Lib/ufo2ft/__init__.py#L223

To match fontmake-py, fontamake-rs could similarly apply its ReverseContourPen by default, and have an option to not to, when building glyf table.

I've always thought that path direction didn't matter, until I stumbled on this: adobe-fonts/source-han-serif#182

[devosb]

I have seen path direction matter in Bengali and Gunjala Gondi scripts. If the directions were not correct, then there would be dropouts in the overlap between consonants and vowel signs. In Windows, using Word, the problem occurred at large point sizes (above 20 or so) and/or zoomed in.

If a single glyph had a mis-oriented contour, I would see it in SILE.