CC-2950: Tell users if they are running an out-of-date version or not

Initial implementation.
- added some code in phone_home_stat to retrieve latest version from stat server
  and store result in db

- created new view helper VersionNotify.php, which queries and calculates version
  difference, then returns the necessary information in html to the view files

- created new javascript file versiontooltip.js, which sets up the qtip stuff so that
  when the version notification icon is clicked, a tooltip is displayed

airtime_mvc/public/js/airtime/dashboard/versiontooltip.js

@@ -0,0 +1,53 @@
+/**
+ * Get the tooltip message to be displayed,
+ * which is stored inside a pair of hidden div tags
+ */
+function getContent() {
+    return $("#version_message").html();
+}
+
+/**
+ * Get the current version,
+ * which is stored inside a pair of hidden div tags
+ */
+function getCurrentVersion() {
+    return $("#version_current").html();
+}
+
+/**
+ * Sets up the tooltip for version notification
+ */
+function setupVersionQtip(){
+    var qtipElem = $('#version_icon');
+    if (qtipElem.length > 0){
+        qtipElem.qtip({
+            id: 'version',
+            content: {
+                text: getContent(),
+                title: {
+                    text: getCurrentVersion(),
+                    button: true
+                }
+            },
+            show: 'click',  /* Show on click */
+            hide: false,    /* Don't hide on mouseout */
+            position: {
+                my: "top right",
+                at: "bottom left"
+            },
+            style: {
+                border: {
+                    width: 0,
+                    radius: 4
+                },
+                classes: "ui-tooltip-dark ui-tooltip-rounded"
+            }
+        });
+    }
+}
+
+$(document).ready(function() {
+    if($('#version_message').length > 0) {
+        setupVersionQtip();
+    }
+});