adding basic meta tags - for ie edge and mobile - to main template header

lms/templates/main.html

@@ -27,6 +27,9 @@
       ## "edX" should not be translated
       <title>edX</title>
 
+      <meta http-equiv="X-UA-Compatible" content="IE=edge">
+      <meta name="viewport" content="width=device-width, initial-scale=1">
+
       <script type="text/javascript">
         /* immediately break out of an iframe if coming from the marketing website */
         (function(window) {