Stay on the right page when we navigate up in the breadcrumb.

Introduce a "show" parameter which contains the id of the item that we
want to show when we go to the parent's page.

themes/default/views/header.html.php

@@ -12,7 +12,7 @@
 <? if ($page_type != "tag"): ?>
 <ul id="gBreadcrumbs">
   <? foreach ($parents as $parent): ?>
-  <li><a href="<?= url::site("albums/{$parent->id}") ?>"><?= $parent->title ?></a></li>
+  <li><a href="<?= url::site("albums/{$parent->id}?show=$item->id") ?>"><?= $parent->title ?></a></li>
   <? endforeach ?>
   <li class="active"><?= $item->title ?></li>
 </ul>