Basic multidatabase support. re #40

TODO :
 * Document the new option
 * Handle URL rewriting
 * Handle bookdetail
 * Test the case without fancybox
 * Update the title with database name

data.php

@@ -132,6 +132,7 @@ class Data extends Base {
                 $urlParam = addURLParameter($urlParam, "height", $height);
             }
             $urlParam = addURLParameter($urlParam, "id", $book->id);
+            if (!is_null (GetUrlParam (DB))) $urlParam = addURLParameter ($urlParam, DB, GetUrlParam (DB));
             return new Link ("fetch.php?" . $urlParam, $mime, $rel, $title);
         }
         else