make menu work with movable apps

lib/helper.php

@@ -41,7 +41,11 @@ class OC_Helper {
 			$app .= '/';
 			// Check if the app is in the app folder
 			if( file_exists( OC::$APPSROOT . '/apps/'. $app.$file )){
-				$urlLinkTo =  OC::$APPSWEBROOT . '/apps/' . $app . $file;
+				if(substr($app, -1, 1) == '/'){
+					$app = substr($app, 0, strlen($app) - 1);
+				}
+				$urlLinkTo =  OC::$WEBROOT . '?app=' . $app;
+				$urlLinkTo .= ($file!='index.php')?'&file=' . $file:'';
 			}
 			else{
 				$urlLinkTo =  OC::$WEBROOT . '/' . $app . $file;