refine code && document

README.md

src/components/Charts/mixchart.vue

src/views/charts/index.vue

src/views/charts/keyboard.vue

src/views/charts/keyboard2.vue

src/views/charts/line.vue

src/views/charts/mixchart.vue

src/views/components/countTo.vue

src/views/components/dndlist.vue

src/views/components/index.vue

src/views/components/jsoneditor.vue

src/views/components/markdown.vue

src/views/errlog/index.vue

src/views/error/401.vue

src/views/error/404.vue

src/views/example/table/dynamictable.vue

src/views/example/table/table.vue

src/views/excel/index.vue

src/views/layout/AppMain.vue

src/views/layout/Layout.vue