Added console.error() in createCallback() function

src/openseadragon.js

@@ -2251,6 +2251,42 @@ function OpenSeadragon( options ){
             event.stopPropagation();
         },
 
+        /**
+         * Similar to OpenSeadragon.delegate, but it does not immediately call
+         * the method on the object, returning a function which can be called
+         * repeatedly to delegate the method. It also allows additional arguments
+         * to be passed during construction which will be added during each
+         * invocation, and each invocation can add additional arguments as well.
+         *
+         * @function
+         * @param {Object} object
+         * @param {Function} method
+         * @param [args] any additional arguments are passed as arguments to the
+         *  created callback
+         * @returns {Function}
+         */
+        createCallback: function( object, method ) {
+            //TODO: This pattern is painful to use and debug.  It's much cleaner
+            //      to use pinning plus anonymous functions.  Get rid of this
+            //      pattern!
+            console.error('The createCallback function is deprecated and will be removed in future versions. Please use alternativeFunction instead.');
+            var initialArgs = [],
+                i;
+            for ( i = 2; i < arguments.length; i++ ) {
+                initialArgs.push( arguments[ i ] );
+            }
+
+            return function() {
+                var args = initialArgs.concat( [] ),
+                    i;
+                for ( i = 0; i < arguments.length; i++ ) {
+                    args.push( arguments[ i ] );
+                }
+
+                return method.apply( object, args );
+            };
+        },
+
 
         /**
          * Retrieves the value of a url parameter from the window.location string.