Enums

[mikowitz]

Map cairo enums to Elixir atoms. For the most part can used the NifUnitEnum derive and From to handle the conversions. PathSegment at least will need NifTaggedEnum, which might require pulling rustler from the master branch.

• Antialias
• BorrowError
• Content
• DeviceType
• Error (partially)
• Extend
• FillRule
• Filter
• FontSlant
• FontType
• FontWeight
• Format
• FtSynthesize
• HintMetrics
• HintStyle
• IoError
• LineCap
• LineJoin
• MeshCorner (unneeded)
• Operator
• PathDataType
• PathSegment
• PatternType
• PdfMetadata
• PdfVersion
• PsLevel
• RegionOverlap
• ScriptMode
• SubpixelOrder
• SurfaceType (created but not used)
• SvgUnit
• SvgVersion
• TextClusterFlags