Fixed problems with the plugins function in WP 3.9.1.  Uses shortcodes now instead for directly inserting the javascript download code which was getting stripped out in TinyMCE visual editor.

git-svn-id: https://plugins.svn.wordpress.org/ics-button/trunk@938566 b8457f37-d9ea-0310-8a92-e5e31aec5664