Use WDN input group markup

Fixed bad padding alignment.

www/templates/search-form.tpl.php

 <div id="searchform" class="wdn-band">
   <form action="./" method="get" class="wdn-inner-wrapper">
-      <div class="input-group">
-        <input type="text" value=""  name="q" id="search_q" title="Search Query" placeholder="e.g., Herbert Husker, Ph.D." />
-        <span class="input-group-btn"><button class="button wdn-icon-search" title="Search" type="submit"></button></span>
+      <div class="wdn-input-group">
+        <input type="text" name="q" id="search_q" aria-label="Search Query" placeholder="e.g., Herbert Husker, Ph.D." />
+        <span class="wdn-input-group-btn"><button class="button wdn-icon-search" type="submit"><span class="wdn-text-hidden">Search</span></button></span>
     </div>
       <?php if (!empty($local_results)): ?>
       <input type="hidden" name="u" value="<?php echo htmlentities($_GET['u'], ENT_QUOTES) ?>" />