Refactored expression variant of ST_MapAlgebra() to be faster.
Performance is almost as good as ST_MapAlgebraExpr(). Ticket #2133

git-svn-id: http://svn.osgeo.org/postgis/trunk@11222 b70326c6-7e19-0410-871a-916f4a2858ee
Code cleanup to shut gcc up

git-svn-id: http://svn.osgeo.org/postgis/trunk@11223 b70326c6-7e19-0410-871a-916f4a2858ee
Added news about Ticket #2133

git-svn-id: http://svn.osgeo.org/postgis/trunk@11224 b70326c6-7e19-0410-871a-916f4a2858ee
Removed commented out variants of ST_MapAlgebra removed in r11222.

git-svn-id: http://svn.osgeo.org/postgis/trunk@11225 b70326c6-7e19-0410-871a-916f4a2858ee