Fixes some positions of elements from the welcome page. Adds "Join Again" button to hangup message box.

app.js

 
     $.prompt("Session Terminated",
         {
-            title: "You hang up the call",
+            title: "You hung up the call",
             persistent: true,
-            buttons: {},
-            closeText: ''
+            buttons: {
+                "Join again": true
+            },
+            closeText: '',
+            submit: function(event, value, message, formVals)
+            {
+                window.location.reload();
+                return false;
+            }
 
         }
     );

css/welcome_page.css

 #brand_header
 {
     background-image:url(../images/welcome_page/header-big.png);
-    position:absolute;
     width: 583px;
     height: 274px;
-    left: 340px;
-    top:15px;
+    margin: -55px auto 0px auto;
 }
 
 #header_text
 {
-    position: absolute;
     left: 200px;
     top: 150px;
     width: 885px;
     font-family: Helvetica;
     font-size: 24px;
     text-align: center;
+    margin: -139px auto 0px auto;
 }
 
 #features