[Config] Fix for priority of New Tab button

WTD-1392
WTD-1359
Set "Open in new tab" button to have priority "preferred";
Set fullscreen mode button to priority "default";
Tweaked full screen button tooltip text;

platform/commonUI/browse/src/windowing/FullscreenAction.js

@@ -29,8 +29,8 @@ define(
     function () {
         "use strict";
 
-        var ENTER_FULLSCREEN = "Enter full screen mode.",
-            EXIT_FULLSCREEN = "Exit full screen mode.";
+        var ENTER_FULLSCREEN = "Enter full screen mode",
+            EXIT_FULLSCREEN = "Exit full screen mode";
 
         /**
          * The fullscreen action toggles between fullscreen display