Fixing typo where clearInterval should be clearTimeout and adding a $this var.

git-svn-id: https://plugins.svn.wordpress.org/mp6/trunk@800154 b8457f37-d9ea-0310-8a92-e5e31aec5664
Switching the widgets js dependancy to admin-widgets, adding a version string, and moving the script to the footer.

git-svn-id: https://plugins.svn.wordpress.org/mp6/trunk@800155 b8457f37-d9ea-0310-8a92-e5e31aec5664