v2.6.0

• Added layerName argument (str) to compileOTF and compileTTF, and layerNames argument (List[Optional[str]]) to compileInterpolatableTTFs, for compiling outlines from a different UFO3 layer than the default UFO layer.
  Note that OpenType features compilation is skipped when layerName is given, as it is assumed that the features.fea only refers to the default UFO layer.
• Added compileInterpolatableTTFsFromDS and compileInterpolatableOTFsFromDS functions that take a FontTools' DesignSpaceDocument object and compile OpenType font masters suitable for generating a variable font. All the SourceDescriptor objects in the designspace should have their font attribute set to a pre-loaded defcon.Font or a compatible UFO Font class. The functions return a copy (or same instance if inplace=True) of the designspace document with the sources' font attributes set to the respective TTFont instances. Sources with layerName attribute (e.g. to define sparse intermediate masters) are also supported: i.e. outlines are converted/compiled compatibly from non-default layers, whereas features are only compiled for
  the default layers.
• [cubicToQuadratic] The Cu2Qu curve_type custom parameter is now stored in the layer's lib element of layerinfo.plist instead of in the global lib.plist, as different layers may well have different curve type.
• Fixed incorrect Family and SubFamily nameIDs (1 and 2) that were generated as fallbacks when UFO fontinfo.plist doesn't explicitly define styleMapFamilyName and styleMapStyleName (#299).
• Bumped minimum installation requirements:
  • fonttools >= 3.35.0
  • cu2qu >= 1.6.5
  • booleanOperations >= 0.8.2