added whole system from ola4doc

sys/node_modules/gulp/lib/taskTree.js

@@ -0,0 +1,14 @@
+'use strict';
+
+module.exports = function(tasks) {
+  return Object.keys(tasks)
+    .reduce(function(prev, task) {
+      prev.nodes.push({
+        label: task,
+        nodes: tasks[task].dep,
+      });
+      return prev;
+    }, {
+      nodes: [],
+    });
+};