allow upgrade from 2.1.2dev, fix copyright notices (e.g. point to postgis.net)

git-svn-id: http://svn.osgeo.org/postgis/trunk@12287 b70326c6-7e19-0410-871a-916f4a2858ee
fix website links to go to postgis.net

git-svn-id: http://svn.osgeo.org/postgis/trunk@12289 b70326c6-7e19-0410-871a-916f4a2858ee