Fix to remove image_cropping jQuery variable from global javascript namespace

The $ variable was removed with jQuery.noConflict(), but that left the jQuery variable still hanging around.  This fixes that by adding "true" as a parameter to noConflict, which also removes the jQuery variable.

Before:
After the page loaded, $.fn.jquery returned the version of my custom jQuery, but jQuery.fn.jquery returned the version of image_cropping's jquery.

Now:
After the page loads, both $.fn.jquery and jQuery.fn.jquery return the version of my custom jQuery.