Several minor bug fixes.
- When iterating over the covered glyphs, CoverageTableData1.as does not call the callback function if it encounters the glyph index 0xFFFF anymore.
- getGlyphIndex of CharacterIndexMappingTableData.as now returns -1 if the requested system or encoding is not present.
- If the ContourParser.as.as encounters contours which have only one vertex in a segment or fewer vertices than endpoints, it will skip these contours.
- Contour.as will not attempt to iterate over non existing Segments anymore.
- EarClippingTriangulator.as will cancel triangulation if it encounters an empty path.