Added error when calling angle2() with a dimension not equal to 2.
Added error when calling angle2() with a dimension not equal to 2.

Also checking that the two points are of equal dimension.

oliverjdb/GoTools,SINTEF-Geometry/GoTools,VibekeSkytt/GoTools,sbriseid/GoTools,oliverjdb/GoTools,VibekeSkytt/GoTools,SINTEF-Geometry/GoTools,SINTEF-Geometry/GoTools,VibekeSkytt/GoTools,sbriseid/GoTools,oliverjdb/GoTools,sbriseid/GoTools