!!!坑：一言以蔽之：npm太慢，需要注册下taobao镜像
新年了，重装了系统，也就需要重装vue devtools了。
clone了vue-devtools包。
安装办法如下：
1. Clone this repo
2. `yarn install`
3. `yarn run dev`
4. A plain shell with a test app will be available at `localhost:8100`.
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使用yarn安装时，始终 提示：waiting，百度后，找到答案：
项目目录下创建.npmrc或.yarnrc（npm安装就建立.npmrc）文件
输入下面得内容搞定
registry "https://registry.npm.taobao.org" sass_binary_site "https://npm.taobao.org/mirrors/node-sass/" phantomjs_cdnurl "http://cnpmjs.org/downloads" electron_mirror "https://npm.taobao.org/mirrors/electron/" sqlite3_binary_host_mirror "https://foxgis.oss-cn-shanghai.aliyuncs.com/" profiler_binary_host_mirror "https://npm.taobao.org/mirrors/node-inspector/" chromedriver_cdnurl "https://cdn.npm.taobao.org/dist/chromedriver"