fix javadoc warnings

git-svn-id: http://zkcalendar.googlecode.com/svn/trunk@169 8cb44ea2-eec7-11de-a004-2f18c49ebcc3
minor tune

git-svn-id: http://zkcalendar.googlecode.com/svn/trunk@170 8cb44ea2-eec7-11de-a004-2f18c49ebcc3
Release 2.1.3

git-svn-id: http://zkcalendar.googlecode.com/svn/trunk@171 8cb44ea2-eec7-11de-a004-2f18c49ebcc3