lwgeom_release (#699), reviewed all usage of lwgeom_release

lwgeom_release (#699), reviewed all usage of lwgeom_release
and replaced with lwgeom_free where possible. Changed the
def'n of lwgeom_release so that it only frees the containing
objects, and not any sub-objects, for those few remaining
cases that required a gentler freeing of objects.

git-svn-id: http://svn.osgeo.org/postgis/trunk@9072 b70326c6-7e19-0410-871a-916f4a2858ee