Wizards: Delay parsing of custom wizards.

... by introducing signal ICore::showNewItemsDialog().

Reviewed-by: Kai Köhne <kai.koehne@nokia.com>

src/plugins/coreplugin/icore.h

@@ -123,6 +123,7 @@ public:
 signals:
     void coreAboutToOpen();
     void coreOpened();
+    void newItemsDialogRequested();
     void saveSettingsRequested();
     void optionsDialogRequested();
     void coreAboutToClose();