Use relative url filter consistently

Author: LalitNM

_includes/sidebar.html

@@ -13,7 +13,7 @@ <h1>
       -->
       <div class="sidebar-logo">
         <a href="http://biopython.org/">
-          <img src="/assets/images/biopython_logo_white.png" alt="Biopython Logo" title="Biopython Home" width="100%"/>
+          <img src={{ "/assets/images/biopython_logo_white.png" | relative_url }} alt="Biopython Logo" title="Biopython Home" width="100%"/>
         </a>
       </div>
       <p class="lead">{{ site.tagline }}</p>
@@ -33,7 +33,7 @@ <h1>
       {% for node in pages_list %}
         {% if node.title != null %}
           {% if node.layout == "page" %}
-            <a class="sidebar-nav-item{% if page.url == node.url %} active{% endif %}" href="{{ node.url }}">{{ node.title }}</a>
+            <a class="sidebar-nav-item{% if page.url == node.url %} active{% endif %}" href={{ node.url | relative_url }}>{{ node.title }}</a>
           {% endif %}
         {% endif %}
       {% endfor %}
@@ -44,7 +44,7 @@ <h1>
       -->
       <a class="sidebar-nav-item" href="{{ site.github.repo }}">GitHub project</a>
     </nav>
-    
+
   </div>
   <div class="sidebar-footer">
       Biopython version {{ site.version }}<br>