Update dev version

git-svn-id: https://plugins.svn.wordpress.org/my-calendar/trunk@795453 b8457f37-d9ea-0310-8a92-e5e31aec5664
Change stable tag to 2.2.13

git-svn-id: https://plugins.svn.wordpress.org/my-calendar/trunk@795457 b8457f37-d9ea-0310-8a92-e5e31aec5664