update into version 2.5

git-svn-id: https://plugins.svn.wordpress.org/scroll-top-and-bottom/trunk@860870 b8457f37-d9ea-0310-8a92-e5e31aec5664
update into version 2.5

git-svn-id: https://plugins.svn.wordpress.org/scroll-top-and-bottom/trunk@860871 b8457f37-d9ea-0310-8a92-e5e31aec5664
bug fix

git-svn-id: https://plugins.svn.wordpress.org/scroll-top-and-bottom/trunk@860905 b8457f37-d9ea-0310-8a92-e5e31aec5664