bump versions to 3.4.2dev (3.4.2)

git-svn-id: http://svn.osgeo.org/geos/branches/3.4@3893 5242fede-7e19-0410-aef8-94bd7d2200fb
update news release date and reminder to do so for future

git-svn-id: http://svn.osgeo.org/geos/branches/3.4@3895 5242fede-7e19-0410-aef8-94bd7d2200fb