Add missing property functions

Here we add

* ST_3DLength
* ST_CoordDim
* ST_CircleCompacity

Note 1: PostGIS does not allow ST_3DLength to take a Polygon as a
parameter. For this purpose, a PostGIS user must use ST_Perimeter, which
was not implemented in GDMS. Should we implement ST_Perimeter?

Note 2: PostGIS also allows MultiLineStrings (for ST_3DLength) and
MultiPolygons (for ST_Perimeter), while GDMS only allowed for
LineStrings and Polygons.