workaround for hiding "new posts" button after selectable_theme was added.

there is conflict between theme "display:block!important" and button hiding.
i tried using a <span> to enclose the <button> but it then broke "float:right", argh.
so setting text to "" seems to hide it.

js/mobile_abstract.js

@@ -104,6 +104,7 @@ var MAL = function()
                 newTweetsBarMenu.addClass("show");
             } else {
                 newTweetsBar.hide();
+                newTweetsBar.text("");
                 newTweetsBarMenu.removeClass("show");
                 document.title = "twister";
             }