Add support for other geometry classes known by WKT

[navibyte]

https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry

Now (at least some level of) support for:

• Point, MultiPoint
• LineString, MultiLineString
• Polygon, MultiPolygon
• GeometryCollection

However NO support for these, and not yet even planned any, is there need?

• Triangle
• PolyhedralSurface
• TIN (Triangulated irregular network)

Well-known binary (WKB) seems to have even more, but maybe most of these are totally out of focus for the geocore library...

• CircularString
• CompoundCurve
• CurvePolygon
• MultiCurve
• MultiSurface
• Curve
• Surface
• Circle
• GeodesicString
• EllipticalCurve
• NurbsCurve
• Clothoid
• SpiralCurve
• CompoundSurface
• BrepSolid
• AffinePlacement