Clarify licensing of PostGIS core as GPL2+ (#2515)

git-svn-id: http://svn.osgeo.org/postgis/trunk@12064 b70326c6-7e19-0410-871a-916f4a2858ee
Cleanup the NEWS file

Drop license change info (#2514) as it's not really new since
we'll be releasing 2.1.1 way before 2.2.0.

git-svn-id: http://svn.osgeo.org/postgis/trunk@12069 b70326c6-7e19-0410-871a-916f4a2858ee