Tree: import checkbox

packages/checkbox/src/checkbox.vue

@@ -18,6 +18,7 @@
         :true-value="trueLabel"
         :false-value="falseLabel"
         v-model="model"
+        @change="$emit('change', $event)"
         @focus="focus = true"
         @blur="focus = false">
       <input
@@ -28,6 +29,7 @@
         :value="label"
         :name="name"
         v-model="model"
+        @change="$emit('change', $event)"
         @focus="focus = true"
         @blur="focus = false">
     </span>

packages/tree/src/tree-node.vue

@@ -40,6 +40,7 @@
 
 <script type="text/jsx">
   import CollapseTransition from './transition';
+  import ElCheckbox from 'element-ui/packages/checkbox'
 
   export default {
     name: 'el-tree-node',
@@ -55,6 +56,7 @@
     },
 
     components: {
+      ElCheckbox,
       CollapseTransition,
       NodeContent: {
         props: {