v3.10.0

• [fontInfoData] The OS/2 vendor ID now defaults to blank (four spaces) instead of NONE when the source has none, as the OS/2 spec recommends and fontc does. The default also appears in name ID 3 (#1009).
• [outlineCompiler] Windows name strings with characters outside the BMP are now written under encoding ID 1 as UTF-16 surrogate pairs, like all other platform 3 strings, instead of encoding ID 10 (#1011, #1012).
• [instantiator] OS/2 weight and width classes are now always derived from the instance's wght and wdth user location, even when the sources set them; the sources' values are only kept when there's no such axis, and public.fontInfo in the instance lib still overrides them (#1014).
• [instantiator] An instance sitting exactly on a source now takes that source's own PANOSE instead of the default's with the disagreeing digits zeroed (#1016).
• [instantiator] An instance sitting exactly on a source now takes that source's public.openTypeCategories instead of the default's, so statics cut from a non-default master no longer lose mark attachments when glyphsLib's per-master GDEF categories differ. Sources that define none fall back to the default's (#1017).