Add Dutch language files

git-svn-id: https://plugins.svn.wordpress.org/lightweight-social-sharing-buttons/trunk@964028 b8457f37-d9ea-0310-8a92-e5e31aec5664
0.3.2 commit

git-svn-id: https://plugins.svn.wordpress.org/lightweight-social-sharing-buttons/trunk@964029 b8457f37-d9ea-0310-8a92-e5e31aec5664