jQuery, jQuery UI and tagging

there are several things rolled up into this pull.  I my mind the most frustrating thing about Ampache has been the fact that tagging is supported in the back end but there is no simple way to tag songs from the web interface.  So I set our to fix that.  I am proposing that Ampache replace prototype.js with jQuery.  This was necessary to build a clean tagging dialog using jQuery UI.  Making this change will also allow the project to tap into the numerous UI widgets, effects and general awesomeness of jQuery UI.  The first use of this is in the simple add tag dialog (pictured below) I built to support tagging songs from the now playing frame and the album page.  The last two change sets cover the jQuery stuff, everything else covers the tagging and I did get it working before doing the adding jquery.  The earlier commits used the javascript prompt to get a tag name from the user.  It was functional but ugly.  The jQuery dialog takes it up a notch.

![9b030bde-2d8a-4235-babc-e80d0dcafbd4](https://f.cloud.github.com/assets/4412332/867192/e57bed30-f6dc-11e2-8602-a436aa194d58.png)