show docs version info more prominently on RTD (#1737)

doc/scripts/divio_docs_theme/layout.html

@@ -125,7 +125,7 @@
     <div class="header">
         <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
         <div class="header-title-wrap">
-            <a class="header-title" href="{{ pathto(master_doc) }}">{{ project }}</a>
+            <a class="header-title" href="{{ pathto(master_doc) }}">{{ project }}</a>{% if READTHEDOCS %} v: {{ current_version }}{% endif %}
         </div>
         <a class="logo-link" target="_blank" href="{{ pathto(master_doc) }}"><img src="{{ pathto('_static/' + logo, 1) }}" class="logo" alt="{{ project }}"/></a>
     </div>