Avoid re-layout when displaying the page.

Use <span>/<span> instead of <ul>/<il> for task menu anchor, to avoid flickering items when the
menus are created.

assets/js/src/base.js

@@ -240,7 +240,7 @@ var Kanboard = (function() {
 
             // Dropdown
             $(".dropit-submenu").hide();
-            $('.dropdown').not(".dropit").dropit();
+            $('.dropdown').not(".dropit").dropit({ triggerParentEl : "span" });
         }
     };