Fix page title on homepage.

Changes logic in _includes/head.html to check for a page.title being set
to the string "Home"

Author: mrmrs

_includes/head.html

@@ -6,10 +6,10 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1">
 
   <title>
-    {% if page.title %}
-      {{ page.title }} &middot; {{ site.title }}
-    {% else %}
+    {% if page.title == "Home" %}
       {{ site.title }} &middot; {{ site.tagline }}
+    {% else %}
+      {{ page.title }} &middot; {{ site.title }}
     {% endif %}
   </title>