added main.css and modified all pages accordingly, modified go.php title section, added some code beauty

lib/php/dashboard.php

@@ -28,6 +28,7 @@
     <head>
         <meta charset="UTF-8">
         <link href="<?=$config['installation_path']?>/favicon.ico" rel="icon" type="image/x-icon">
+        <link href="<?=$config['installation_path']?>/lib/css/main.css" rel="stylesheet">
         <link href="<?=$config['installation_path']?>/lib/css/manage.css" rel="stylesheet">
         <title>Dashboard Home | <?=$config['website_name']?></title>
     </head>