Use github metadata for links to github

_layouts/eip.html

@@ -5,7 +5,7 @@
 <div class="home">
   <h1 class="page-heading">
     EIP {{ page.eip | xml_escape }}: {{ page.title | xml_escape }}
-    <a href="https://github.com/ethereum/EIPs/blob/master/{{page.path}}"><svg role="img" aria-label="Source" xmlns="http://www.w3.org/2000/svg" width="14" height="16" viewBox="0 0 14 16"><title>Source</title><path fill-rule="evenodd" d="M9.5 3L8 4.5 11.5 8 8 11.5 9.5 13 14 8 9.5 3zm-5 0L0 8l4.5 5L6 11.5 2.5 8 6 4.5 4.5 3z"/></svg></a>
+    <a href="{{site.github.repository_url}}/blob/master/{{page.path}}"><svg role="img" aria-label="Source" xmlns="http://www.w3.org/2000/svg" width="14" height="16" viewBox="0 0 14 16"><title>Source</title><path fill-rule="evenodd" d="M9.5 3L8 4.5 11.5 8 8 11.5 9.5 13 14 8 9.5 3zm-5 0L0 8l4.5 5L6 11.5 2.5 8 6 4.5 4.5 3z"/></svg></a>
   </h1>
   <table>
     <tr><th>Author</th><td>{% include authorlist.html authors=page.author %}</td></tr>

index.html

@@ -3,7 +3,7 @@
 title: Home
 ---
 
-<a href="https://github.com/ethereum/EIPs/"><img style="position: absolute; top: 0; right: 0; border: 0;" src="https://s3.amazonaws.com/github/ribbons/forkme_right_darkblue_121621.png" alt="Fork me on GitHub"></a>
+<a href="{{site.github.repository_url}}"><img style="position: absolute; top: 0; right: 0; border: 0;" src="https://s3.amazonaws.com/github/ribbons/forkme_right_darkblue_121621.png" alt="Fork me on GitHub"></a>
 
 <h1 class="page-heading">EIPs <a href="https://gitter.im/ethereum/EIPs?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge"><img src="https://badges.gitter.im/Join%20Chat.svg" alt="Gitter"></a></h1>
 <p>Ethereum Improvement Proposals (EIPs) describe standards for the Ethereum platform, including core protocol specifications, client APIs, and contract standards.</p>