version 0.6.4

git-svn-id: https://plugins.svn.wordpress.org/widget-embed-lastest-tweets/trunk@953529 b8457f37-d9ea-0310-8a92-e5e31aec5664
update script version number

git-svn-id: https://plugins.svn.wordpress.org/widget-embed-lastest-tweets/trunk@953537 b8457f37-d9ea-0310-8a92-e5e31aec5664