version 0.3.1

git-svn-id: https://plugins.svn.wordpress.org/2048-number-game/trunk@942978 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme

git-svn-id: https://plugins.svn.wordpress.org/2048-number-game/trunk@942980 b8457f37-d9ea-0310-8a92-e5e31aec5664