Display site subtitle in masthead (#2205)

* Add site subtitle
* Tabs vs spaces - the ancient conflict
* updates cfr PR #2205
* Perhaps also add the closing anchor
* Make sure we check for the right variables...
* Brown paper bag - subtitle, not description

_includes/masthead.html

@@ -11,7 +11,9 @@
         {% unless logo_path == empty %}
           <a class="site-logo" href="{{ '/' | relative_url }}"><img src="{{ logo_path | relative_url }}" alt=""></a>
         {% endunless %}
-        <a class="site-title" href="{{ '/' | relative_url }}">{{ site.masthead_title | default: site.title }}</a>
+        <a class="site-title" href="{{ '/' | relative_url }}">{{ site.masthead_title | default: site.title }}
+        {% if site.subtitle %}<div class="site-subtitle">{{ site.subtitle }}</div>{% endif %}
+	</a>
         <ul class="visible-links">
           {%- for link in site.data.navigation.main -%}
             {%- if link.url contains '://' -%}

_sass/minimal-mistakes/_masthead.scss

@@ -53,6 +53,10 @@
   z-index: 20;
 }
 
+.site-subtitle {
+  font-size: $type-size-8;
+}
+
 .masthead__menu {
   float: left;
   margin-left: 0;