feat(dropdown): simple temporary cache clear

Adds another behavior "clear cache" which temporary disables the api cache at the next remote call.
This allows for just temporary clearing the cache if "apiSettings; {cache: false}" (for no cache at all) is not desired

Author: lubber-de

src/definitions/modules/dropdown.js

@@ -102,7 +102,8 @@
                 selectObserver,
                 menuObserver,
                 classObserver,
-                module
+                module,
+                tempDisableApiCache = false
             ;
 
             module = {
@@ -869,11 +870,12 @@
                     if (!$module.api('get request')) {
                         module.setup.api();
                     }
-                    apiSettings = $.extend(true, {}, apiSettings, settings.apiSettings, apiCallbacks);
+                    apiSettings = $.extend(true, {}, apiSettings, settings.apiSettings, apiCallbacks, tempDisableApiCache ? { cache: false } : {});
                     $module
                         .api('setting', apiSettings)
                         .api('query')
                     ;
+                    tempDisableApiCache = false;
                 },
 
                 filterItems: function (query) {
@@ -2399,6 +2401,11 @@
                     module.set.value('', null, null, preventChangeTrigger);
                 },
 
+                clearCache: function () {
+                    module.debug('Clearing API cache once');
+                    tempDisableApiCache = true;
+                },
+
                 scrollPage: function (direction, $selectedItem) {
                     var
                         $currentItem  = $selectedItem || module.get.selectedItem(),
@@ -3449,7 +3456,7 @@
                         return settings.apiSettings && module.can.useAPI();
                     },
                     noApiCache: function () {
-                        return settings.apiSettings && !settings.apiSettings.cache;
+                        return tempDisableApiCache || (settings.apiSettings && !settings.apiSettings.cache);
                     },
                     single: function () {
                         return !module.is.multiple();