Upgrade to Nuxt 1.0.0-alpha4, Koa 2.3, Element 1.3.7 and some improvements
- upgrade Element-UI to 1.3.7
- upgrade Nuxt to 1.0.0-alpha4 (now use Vue 2.3.x and look forward to Nuxt 1.0.0 release)
- upgrade to Koa 2.3 and its plugins
- upgrade ESlint
- upgrade Webpack to 3.0
- support jwt expiration
- add koa logger injection (use ctx.log)
- integrate Chart.js
- support i18n and auto-detect locale
- fetch menu from backend
- add demo for charts