Use a double for PrecisionModel scale, avoiding overflows

Fixes #652

git-svn-id: http://svn.osgeo.org/geos/trunk@3907 5242fede-7e19-0410-aef8-94bd7d2200fb
Set JTS_PORT for CMake in sync with others

.. we should really reduce the number of places version is set

git-svn-id: http://svn.osgeo.org/geos/trunk@3908 5242fede-7e19-0410-aef8-94bd7d2200fb