update stable tag

git-svn-id: https://plugins.svn.wordpress.org/appointment-booking-calendar-by-click4time/trunk@849488 b8457f37-d9ea-0310-8a92-e5e31aec5664
update version 2.0 tag

git-svn-id: https://plugins.svn.wordpress.org/appointment-booking-calendar-by-click4time/trunk@849489 b8457f37-d9ea-0310-8a92-e5e31aec5664