issue: Adds osTicket Favicons

This addresses issue 4112 where osTicket does not have a default favicon.
This adds favicon images and references to them in the Agent and
Client headers so they appear correctly.

include/client/header.inc.php

@@ -42,6 +42,9 @@ if ($lang) {
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH; ?>css/flags.css">
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH; ?>css/rtl.css"/>
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH; ?>css/select2.min.css">
+    <!-- Favicons -->
+    <link rel="icon" type="image/png" href="<?php echo ROOT_PATH ?>images/oscar-favicon-32x32.png" sizes="32x32" />
+    <link rel="icon" type="image/png" href="<?php echo ROOT_PATH ?>images/oscar-favicon-16x16.png" sizes="16x16" />
     <script type="text/javascript" src="<?php echo ROOT_PATH; ?>js/jquery-1.11.2.min.js"></script>
     <script type="text/javascript" src="<?php echo ROOT_PATH; ?>js/jquery-ui-1.10.3.custom.min.js"></script>
     <script src="<?php echo ROOT_PATH; ?>js/osticket.js"></script>

include/staff/header.inc.php

@@ -44,6 +44,9 @@ if ($lang) {
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH; ?>css/select2.min.css">
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH; ?>css/rtl.css"/>
     <link type="text/css" rel="stylesheet" href="<?php echo ROOT_PATH ?>scp/css/translatable.css"/>
+    <!-- Favicons -->
+    <link rel="icon" type="image/png" href="<?php echo ROOT_PATH ?>images/oscar-favicon-32x32.png" sizes="32x32" />
+    <link rel="icon" type="image/png" href="<?php echo ROOT_PATH ?>images/oscar-favicon-16x16.png" sizes="16x16" />
 
     <?php
     if($ost && ($headers=$ost->getExtraHeaders())) {