fix(template): download book with capital ext by kindle's browser

cps/templates/detail.html

@@ -22,7 +22,7 @@
                     {{_('Download')}} :
                   </button>
                   {% for format in entry.data %}
-                  <a href="{{ url_for('get_download_link_ext', book_id=entry.id, book_format=format.format|lower, anyname=entry.id|string+'.'+format.format) }}" id="btnGroupDrop1{{format.format|lower}}" class="btn btn-primary" role="button">
+                  <a href="{{ url_for('get_download_link_ext', book_id=entry.id, book_format=format.format|lower, anyname=entry.id|string+'.'+format.format|lower) }}" id="btnGroupDrop1{{format.format|lower}}" class="btn btn-primary" role="button">
                     <span class="glyphicon glyphicon-download"></span>{{format.format}} ({{ format.uncompressed_size|filesizeformat }})
                   </a>
                   {% endfor %}
@@ -33,7 +33,7 @@
                   </button>
                   <ul class="dropdown-menu" aria-labelledby="btnGroupDrop1">
                   {% for format in entry.data %}
-                    <li><a href="{{ url_for('get_download_link_ext', book_id=entry.id, book_format=format.format|lower, anyname=entry.id|string+'.'+format.format) }}">{{format.format}} ({{ format.uncompressed_size|filesizeformat }})</a></li>
+                    <li><a href="{{ url_for('get_download_link_ext', book_id=entry.id, book_format=format.format|lower, anyname=entry.id|string+'.'+format.format|lower) }}">{{format.format}} ({{ format.uncompressed_size|filesizeformat }})</a></li>
                   {% endfor %}
                   </ul>
                 {% endif %}