Provide test glyphs files which exercise all Glyphs functionality

[simoncozens]

• A file with linked masters
• A file with feature replacement
• A file with smart components
• A file with all special anchors
• Anchor propagation - with expectations for how it should be compiled
• A file which generates all the automatic features which Glyphs generates - with expectations for how it should be compiled
• A file with outside open corners - with expectations for how they should be removed
• A file with color layers (of various different formats), strokes and fills
• A file with different marks - with expectations of when they are zeroed and when they are not
  • with components of them which are shifted/rotated/etc.
• A file with localised metadata names
• A file with bracket layers, brace layers, double-ended alternate layers, ...
• ...

[schriftgestalt]

The file at https://github.com/schriftgestalt/GlyphsSDK/blob/Glyphs3/GlyphsFileFormat/GlyphsFileFormatv3.glyphs is supposed to be that. If you find anything missing, either notify my, or send a pull request.