Add meta and OG

[mattstauffer]

Fixes #47

Output::

            <!-- Schema.org markup for Google+ -->
        <meta itemprop="name" content="Introducing Gistlog landing pages">
        <meta itemprop="description" content="It&#039;s great that Gistlog makes it easy to write Gist-powered, Markdown-formatted, blog posts. But what if you want to use it as your entire blogging platform? We&#039;re working on it, and here&#039;s a first step:">

        <!-- Open Graph data -->
        <meta property="og:title" content="Introducing Gistlog landing pages">
        <meta property="og:type" content="article">
        <meta property="og:url" content="http://localhost:8095/mattstauffer/a82db51468a02f53442d">
        <meta property="og:description" content="It&#039;s great that Gistlog makes it easy to write Gist-powered, Markdown-formatted, blog posts. But what if you want to use it as your entire blogging platform? We&#039;re working on it, and here&#039;s a first step:">
        <meta property="og:site_name" content="Gistlog">

[adamwathan]

Double strip tags?

[mattstauffer]

whoops!

[adamwathan]

👍