add vue-draggable-nested-tree (vuejs#2079)

* add vue-draggable-nested-tree

* moved to list end

* moved to Tree list end

* moved to Tree list end

README.md

@@ -1064,6 +1064,7 @@ Tooltips / popovers
  - [Bosket](https://github.com/elbywan/bosket) - Collection of tree view components for front-end frameworks (Vue, React, Angular and Riot).
  - [plantain-00/tree-component](https://github.com/plantain-00/tree-component) - A reactjs, angular and vuejs tree component.
  - [sl-vue-tree](https://github.com/holiber/sl-vue-tree) - A simple customizable draggable tree component for Vue.js
+ - [vue-draggable-nested-tree ★0](https://github.com/phphe/vue-draggable-nested-tree): Customizable draggable tree view component for Vuejs2 [@phphe](https://github.com/phphe)
 
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