fixing issue with jquery 1.10.0+ when no comments are present

This fixes an issue if this plugin is running on jQuery 1.10.0 or above, and no comments are in the target element.

jQuery replaces the element with nothing, which removes the element. This change makes elements remain if they have no replacement comment, which allows developers to still use it for calling the `load` callback, events, etc, even when they don't need to replace the whole element.