DOC: Fix doc sidebar

Closes gh-1068

Author: effigies

doc/source/_static/nibabel.css

@@ -4,6 +4,10 @@ body {
     background-color: #E5E2E2;
 }
 
+div.sphinxsidebar {
+    position: relative;
+}
+
 div.sphinxsidebar h4, div.sphinxsidebar h3 {
     background-color: #2F83C8;
 }

doc/source/_templates/layout.html

@@ -8,6 +8,9 @@
   <li><a href="legal.html">License</a> |&nbsp;</li>
 {% endblock %}
 
+{% block sidebar1 %}{{ sidebar() }}{% endblock %}
+{% block sidebar2 %}{% endblock %}
+
 {% block extrahead %}
   <meta name="keywords" content="nipy, neuroimaging, python, neuroscience">
 {% endblock %}
@@ -30,6 +33,3 @@ <h3 style="margin-top:-5px;color:#2f83c8">Access a cacophony of neuro-imaging fi
 {% endblock %}
 
 {% block relbar2 %}{% endblock %}
-
-{% block sidebar1 %}{{ sidebar() }}{% endblock %}
-{% block sidebar2 %}{% endblock %}