Fix annotation deletion

Closes #12

capsule-prototype/js/PopupPanelWidget.js

@@ -925,7 +925,7 @@ PopupPanelWidget.prototype.createPopupContent = function (tag) {
             }
             deleteElement
                 .click(function () {
-                    window.app.rekall.Rekall('pubSub').publish('', {
+                    window.app.rekall.Rekall('pubSub').publish('alert', {
                         message: "Do you really want to delete this file from the project ?",
                         buttons: "yesnodelete"
                     });