article: introduction to template element
revised template article + added cover image
replaced &lt;template&gt; with `<template>`
reflected feedback
added trackable url to HTML5Rocks article link
Merge remote-tracking branch 'upstream/site' into template
fixed a bug on jsbin. replaced URL in template element article.
Merge pull request #163 from agektmr/template

URL change for jsbin.com in template article