add dev mode, update readme

dev/App.vue

@@ -0,0 +1,84 @@
+<template>
+    <div>
+        <button @click="addNode">Add Node</button>
+        <vue-tree-list @click="onClick" :model="data" default-tree-node-name="new node" default-leaf-node-name="new leaf"></vue-tree-list>
+        <button @click="getNewTree">Get new tree</button>
+        <pre>
+          {{newTree}}
+        </pre>
+    </div>
+</template>
+<script>
+  import { VueTreeList, Tree, TreeNode } from '../src'
+  export default {
+    components: {
+      VueTreeList
+    },
+    data () {
+      return {
+        newTree: {},
+        data: new Tree([
+          {
+            name: 'Node 1',
+            id: 1,
+            pid: 0,
+            dragDisabled: true,
+            children: [
+              {
+                name: 'Node 1-2',
+                id: 2,
+                isLeaf: true,
+                pid: 1
+              }
+            ]
+          },
+          {
+            name: 'Node 2',
+            id: 3,
+            pid: 0,
+            dragDisabled: true
+          },
+          {
+            name: 'Node 3',
+            id: 4,
+            pid: 0
+          }
+        ])
+      }
+    },
+    methods: {
+      addNode: function () {
+        var node = new TreeNode({ name: 'new node', isLeaf: false })
+        if (!this.data.children) this.data.children = []
+        this.data.addChildren(node)
+      },
+
+      getNewTree: function () {
+        var vm = this
+        function _dfs (oldNode) {
+          var newNode = {}
+
+          for (var k in oldNode) {
+            if (k !== 'children' && k !== 'parent') {
+              newNode[k] = oldNode[k]
+            }
+          }
+
+          if (oldNode.children && oldNode.children.length > 0) {
+            newNode.children = []
+            for (var i = 0, len = oldNode.children.length; i < len; i++) {
+              newNode.children.push(_dfs(oldNode.children[i]))
+            }
+          }
+          return newNode
+        }
+
+        vm.newTree = _dfs(vm.data)
+      },
+
+      onClick(model) {
+        console.log(model)
+      }
+    }
+  }
+</script>