Add ST_IsRectangle
Add ST_IsValid
Add ST_Covers
Add ST_DWithin

The following GDMS functions have been replaced by their H2GIS
equivalents:

        GDMS                    H2GIS
        ST_IsWithin             ST_Within  (h2spatial -- SFS)
        ST_IsWithinDistance     ST_DWithin (h2spatial-ext)

Note also that PostGIS contains the function ST_CoveredBy which seems to
do the same thing as ST_Within.
Merge pull request #26 from agouge/predicate-functions

Implement missing predicate functions
Add myself to the list of developers
Fix failing Jenkins build.

I forgot to DROP TABLE (IF EXISTS).
Merge pull request #27 from agouge/fix-jenkins-build

[Quick fix] Fix failing Jenkins build
Add ST_XMax
Add ST_XMin, ST_YMin and ST_YMax
Add ST_ZMin and ST_ZMax
Merge pull request #28 from agouge/min-max-fns

Add ST_XYZMinMax
Move ST_Extent from aggregate to properties pkg
Move ST_Explode from table to properties pkg
Merge pull request #30 from agouge/small-refactor

Small refactor
Add ST_Rotate

Note: By default, PostGIS rotates a geometry about POINT(0,0), while
GDMS rotated the geometry about the center of its internal envelope.

TODO: Allow the user to rotate a geometry about an arbitrary point, via
        ST_Rotate(Geometry geom, double theta, double x0, double y0)
        ST_Rotate(Geometry geom, double theta, Geometry pointOrigin)
Allow rotation about an arbitrary point
Fix some naming problems from copy-paste.
Add ST_Scale.

Note: In GDMS, we had the function
        ST_Scale(geom, scale)

In PostGIS, we have the functions
        ST_Scale(geom, xScale, yScale)
        ST_Scale(geom, xScale, yScale, zScale)

I.e., in GDMS, we assumed xScale=yScale. I decided to undo this
unnecessary coupling and also allow the user to scale the z-coordinate.
This amounted to conforming to PostGIS.
Fix pom version