work around a bug in iOS 6 where ajax requests get cached and only work once

octoprint/static/js/ui.js

@@ -1391,6 +1391,12 @@ $(function() {
             webcamViewModel,
             gcodeViewModel
         );
+        
+        //work around a stupid iOS6 bug where ajax requests get cached and only work once, as described at http://stackoverflow.com/questions/12506897/is-safari-on-ios-6-caching-ajax-results
+        $.ajaxSetup({
+		    type: 'POST',
+		    headers: { "cache-control": "no-cache" }
+		});
 
         //~~ Show settings - to ensure centered
         $('#navbar_show_settings').click(function() {