add 2.0.3 and 2.1 sections, break out 2.1 changed from new

git-svn-id: http://svn.osgeo.org/postgis/trunk@11339 b70326c6-7e19-0410-871a-916f4a2858ee
#2262 change box cast from implicit to assignment

git-svn-id: http://svn.osgeo.org/postgis/trunk@11340 b70326c6-7e19-0410-871a-916f4a2858ee