Allow to specific standalone app idle time

dgl/Application.hpp

@@ -62,7 +62,7 @@ public:
       idle() is called at regular intervals.
       @note This function is meant for standalones only, *never* call this from plugins.
     */
-    void exec();
+    void exec(int idleTime = 10);
 
    /**
       Quit the application.

dgl/src/Application.cpp

@@ -44,12 +44,12 @@ void Application::idle()
     }
 }
 
-void Application::exec()
+void Application::exec(int idleTime)
 {
     for (; pData->doLoop;)
     {
         idle();
-        d_msleep(10);
+        d_msleep(idleTime);
     }
 }