dashboard: disable screenshot button if screenshot is in progress

circle/dashboard/static/dashboard/vm-details.js

@@ -268,9 +268,21 @@ $(function() {
   $("#getScreenshotButton").click(function() {
     var vm = $(this).data("vm-pk");
     var ct = $("#vm-console-screenshot");
+    $("i", this).addClass("icon-spinner icon-spin");
+    $(this).prop("disabled", true);
     ct.slideDown();
     var img = $("img", ct).prop("src", '/dashboard/vm/' + vm + '/screenshot/');
   });
+
+  // if the image is loaded remove the spinning stuff
+  // note: this should not work if the image is cached, but it's not
+  // see: http://stackoverflow.com/a/3877079/1112653
+  $("#vm-console-screenshot img").load(function(e) {
+    $("#getScreenshotButton").prop("disabled", false)
+    .find("i").removeClass("icon-spinner icon-spin");
+
+  });
+    
   
   // screenshot close
   $("#vm-console-screenshot button").click(function() {