Allow callback function to be set as lookup in options. Fixes devbridge#227

Author: Tomas Kirda

src/jquery.autocomplete.js

@@ -541,8 +541,8 @@
                 return;
             }
 
-            if ($.isFunction(that.lookup)){
-                that.lookup(q, function (data) {
+            if ($.isFunction(options.lookup)){
+                options.lookup(q, function (data) {
                     that.suggestions = data.suggestions;
                     that.suggest();
                     options.onSearchComplete.call(that.element, q, data.suggestions);