v2.3: Fixed: Category change from a single category to another

git-svn-id: https://plugins.svn.wordpress.org/oik-batchmove/trunk@994156 b8457f37-d9ea-0310-8a92-e5e31aec5664
v2.3: Make 2.3 the stable version

git-svn-id: https://plugins.svn.wordpress.org/oik-batchmove/trunk@994159 b8457f37-d9ea-0310-8a92-e5e31aec5664