* Support sbix Glyphs with graphicType = "flip"
Since iOS 17.4 beta, Apple introduced the "flip" graphic type for the sbix glyphs to reference the another glyph to be flipped by their render engine. Their use case is for directional emojis.
Example emoji: https://emojipedia.org/woman_walking_facing_right#technical
This is the example of the output XML after this PR:
```
<glyph graphicType="flip" name="u1F3C3.0.M.u27A1" originOffsetX="0" originOffsetY="0">
<ref glyphname="u1F3C3.0.M" />
</glyph>
```
Before, it was just `<hexdata>` with some data in it.
technically we are tweaking the original example from the spec but it keeps the spirit, so that the product of glyph classes produces the same representation in the font as if the sequences were manually enumerated (while keeping the declaration order)
* Add optional transformRoundFunc to RoundingPen and RoundingPointPen
* Add tests
* Add doc about comparing UFO to TTF glyphs
* Use floatToFixedToFloat for example with rounding
the latest lxml.etree.fromstring complains with syntax error when the xml declaration contain 'standalone' but does not contain encoding, apparently the xml declaration attributes have predefined order
https://github.com/actions/upload-artifact?tab=readme-ov-file#breaking-changes
> Due to how Artifacts are created in this new version, it is no longer possible to upload to the same named Artifact multiple times. You must either split the uploads into multiple Artifacts with different names, or only upload once. Otherwise you will encounter an error.
This caused the PyPI upload job to fail earlier. Hopefully this should fix it.
If a FeatureVariationRecord with the same ConditionTable exists re-use
it and append FeatureTableSubstitutionRecord’s.
Without this, in the following feature code only the first lookup will
be applied since there will be two FeatureVariationRecord with the same
ConditionTable, so the first will be matched and the other will be
skipped:
conditionset test {
wght 600 1000;
wdth 150 200;
} test;
variation ccmp test {
sub e by a;
} ccmp;
variation rlig test {
sub b by c;
} rlig;
With this change only one FeatureVariationRecord will be created with
two FeatureTableSubstitutionRecord’s.
