CC-2950: Tell users if they are running an out-of-date version or not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/application/layouts/scripts/layout.phtml

@@ -10,6 +10,7 @@
 
 <div id="Panel">
     <div class="logo"></div>
+    <?php echo $this->versionNotify() ?>
     <?php echo $this->partial('partialviews/header.phtml', array("user" => $this->loggedInAs(), "is_trial"=>$this->isTrial(), "trial_remain"=> $this->trialRemaining())) ?>
 
 <?php 	$partial = array('menu.phtml', 'default');

airtime_mvc/application/layouts/scripts/library.phtml

@@ -10,6 +10,7 @@
 
 <div id="Panel">
     <div class="logo"></div>
+    <?php echo $this->versionNotify() ?>
     <?php echo $this->partial('partialviews/header.phtml', array("user" => $this->loggedInAs(), "is_trial"=>$this->isTrial(), "trial_remain"=> $this->trialRemaining())) ?>
 
 <?php 	$partial = array('menu.phtml', 'default');