Give the focus to the search field when going to the Home section.

It outlines the search field, which makes it more visible. It also makes the keyboard appear on mobile device, which invites the user to type something
It makes it a bit more clear for the user on what to do
Fixes #40

js/app.js

@@ -46,6 +46,7 @@ define(function(require) {
         if ($('#navbarToggle').is(":visible") && $('#liHomeNav').is(':visible')) {
             $('#navbarToggle').click();
         }
+        $('#prefix').focus();
         return false;
     });
     $('#btnConfigure').on('click', function(e) {