Update SB Core version 1.4.4

git-svn-id: https://plugins.svn.wordpress.org/sb-core/trunk@1049167 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme file

git-svn-id: https://plugins.svn.wordpress.org/sb-core/trunk@1049175 b8457f37-d9ea-0310-8a92-e5e31aec5664