added favicons and some optis

package.json

src/.vuepress/config.js

src/.vuepress/public/icons/android-chrome-192x192.png

src/.vuepress/public/icons/android-chrome-512x512.png

src/.vuepress/public/icons/apple-touch-icon-precomposed.png

src/.vuepress/public/icons/apple-touch-icon.png

src/.vuepress/public/icons/browserconfig.xml

src/.vuepress/public/icons/favicon-16x16.png

src/.vuepress/public/icons/favicon-32x32.png

src/.vuepress/public/icons/favicon.ico

src/.vuepress/public/icons/mstile-150x150.png

src/.vuepress/public/icons/mstile-310x150.png

src/.vuepress/public/icons/mstile-310x310.png

src/.vuepress/public/icons/mstile-70x70.png

src/.vuepress/public/icons/safari-pinned-tab.svg

src/.vuepress/theme/components/Footer.vue

src/.vuepress/theme/styles/index.styl

src/.vuepress/theme/styles/palette.styl

src/components/links.md

src/introduction/README.md