Major performance improvements to the Dashboard and Calendar views

* Close the PHP session for writing as early as possible in most AJAX
  calls for those views
* Reduce the number of roundtrips to the server in both the Dashboard
  and Calendar views by putting the data in our HTML response (this
  makes a massive difference)
* Eliminated a couple of unneccessary AJAX calls
* Use lazy loading in full calendar
* Fixed a bug in the week view that only occurs near the end of the
  week (date->gmdate bug!)

airtime_mvc/public/js/airtime/library/library.js

@@ -890,7 +890,7 @@ var AIRTIME = (function(AIRTIME) {
             }
         });
        
-        checkImportStatus();
+        //checkImportStatus();
         checkLibrarySCUploadStatus();
         
         addQtipToSCIcons();