Fix issue where themes were not applied immediately

web/templates/header.html

@@ -5,7 +5,7 @@
   <link rel="icon" href="/images/favicon.ico" type="image/x-icon">
   <title><?php echo $_SERVER['HTTP_HOST']; ?> - <?=__($TAB)?> - <?=__('Hestia Control Panel');?></title>
   <link type="text/css" rel="stylesheet" href="/css/styles.min.css?1446554103" />
-  <link type="text/css" rel="stylesheet" href="/css/active-theme.css?1446554103" />
+  <link type="text/css" rel="stylesheet" href="/css/active-theme.css?<?php echo rand() ?>" />
   <link type="text/css" href="/css/animate.css?1446554103" rel="stylesheet" />
   <link type="text/css" href="/css/jquery-custom-dialogs.css?1446554103" rel="stylesheet" />
   <link type="text/css" href="/css/all.min.css?1446554103" rel="stylesheet" />