Merge pull request #183 from SBoudrias/patch-1

"this" isn't referring the right object...

jquery.isotope.js

@@ -811,7 +811,7 @@
         instance.$allAtoms = instance.$allAtoms.not( $content );
         $content.remove();
         if ( callback ) {
-          callback.call( this.element );
+          callback.call( instance.element );
         }
       };