Add cancel action for active app tasks

src/views/apps.js

@@ -456,6 +456,29 @@ angular.module('Application').controller('AppsController', ['$scope', '$location
         }
     };
 
+    $scope.appCancel = {
+        app: {},
+        busy: false,
+
+        show: function (app) {
+            $scope.appCancel.app = app;
+            $scope.appCancel.busy = false;
+
+            $('#appCancelModal').modal('show');
+        },
+
+        submit: function () {
+            Client.stopTask($scope.appCancel.app.taskId, function (error) {
+                if (error) Client.error(error);
+                $scope.appCancel.busy = false;
+
+                $('#appCancelModal').modal('hide');
+            });
+
+            return false; // prevent propagation and default
+        }
+    };
+
     $scope.appInfo = {
         app: {},
         message: ''