Make the Open Graph debugger happy.

Why they don't comply with their own spec is beyond me.

Author: mblayman

_includes/og.html

@@ -1,6 +1,7 @@
 <meta property="og:type" content="website" />
 <meta property="og:title" content="{{ site.title }}" />
 <meta property="og:url" content="{{ site.url }}" />
+<meta property="og:image" content="{{ site.url }}{% link img/logos/pythonfrederick.jpg %}" />
 <meta property="og:image:url" content="{{ site.url }}{% link img/logos/pythonfrederick.jpg %}" />
 <meta property="og:image:width" content="600" />
 <meta property="og:image:height" content="596" />