Prevent html encoding artifacts

Change .html() to .text() so that special html characters (ie, '<', '>') are not encoded when using this control in single select mode.
Fix memory leaks.

 - MultiSelect: Form events not being unbound on destroy.
 - Filter: Document events not being unbound on destroy.
 - Filter: Removed circular reference that prevented garbage collection.

Have not updated minified javascript!
prevent empty text in ui object when title attribute isn't provided to option tags