Add support for author metadata to be included in the post page

This is currently not linked, and the only author I have added is for a post I'm
backporting

Author: rtyler

.gitignore

@@ -3,3 +3,4 @@ _site
 .jekyll-cache
 .jekyll-metadata
 vendor
+*.sw*

_data/authors.yml

@@ -0,0 +1,13 @@
+#
+# This data file contains all the authors for the blog, with their links,
+# description, etc
+---
+
+gwtrev:
+  name: George Treviranus
+  twitter: gwtrev
+  about: |
+    George is a front-end developer and digital designer living in Oakland,
+    California. By day, he’s a front-end software engineer at Scribd. Other
+    times, he can be found long boarding, playing video games, or napping.
+    Usually napping.

_layouts/post.html

@@ -13,7 +13,7 @@ <h1 itemprop="name headline">{{ page.title | escape }}</h1>
             </time>
 
             {%- if page.author -%}
-            • <span itemprop="author" itemscope itemtype="http://schema.org/Person"><span itemprop="name">{{ page.author }}</span></span>
+            • <span itemprop="author" itemscope itemtype="http://schema.org/Person"><span itemprop="name">{{ site.data.authors[page.author].name }}</span></span>
             {%- endif -%}
         </p>
     </header>