readme.txt change stable tag to 1.2

git-svn-id: https://plugins.svn.wordpress.org/better-extended-live-archive/trunk@910587 b8457f37-d9ea-0310-8a92-e5e31aec5664
change stable tag to 1.3

git-svn-id: https://plugins.svn.wordpress.org/better-extended-live-archive/trunk@910589 b8457f37-d9ea-0310-8a92-e5e31aec5664