Base expected TopoGeo_addLinestring output on GEOS version (#2368)

git-svn-id: http://svn.osgeo.org/postgis/branches/2.0@11613 b70326c6-7e19-0410-871a-916f4a2858ee
#876 ST_Azimuth doc patch - close my eyes and accept this patch

git-svn-id: http://svn.osgeo.org/postgis/branches/2.0@11615 b70326c6-7e19-0410-871a-916f4a2858ee
#2242 clarify the behavior of ST_Union (agg) that it is like other aggs ignoring nulls and ST_Union(geom1,geom2) that is alike string concat any element that is null will force the whole output to be null.

git-svn-id: http://svn.osgeo.org/postgis/branches/2.0@11618 b70326c6-7e19-0410-871a-916f4a2858ee