fixes #1419 add photos in a lounge as a temporary space

* at the end of the upload of after a maximum duration, move the photos from the lounge to their actual categories.
* do not invalidate user cache when photos are added in the lounge, thus avoiding to rebuild cache on every photo uploaded
* the lounge system activates itself only beyond 50k (by default) photo

include/ws_functions/pwg.images.php

@@ -405,8 +405,10 @@ SELECT id, name, permalink, uppercats, global_rank, commentable
   }
   usort($related_categories, 'global_rank_compare');
 
-  if (empty($related_categories))
+  if (empty($related_categories) and !is_admin())
   {
+    // photo might be in the lounge? or simply orphan. A standard user should not get
+    // info. An admin should still be able to get info.
     return new PwgError(401, 'Access denied');
   }
 
@@ -2094,6 +2096,21 @@ function ws_images_checkUpload($params, $service)
   return $ret;
 }
 
+/**
+ * API method
+ * Empties the lounge, where photos may wait before taking off.
+ * @since 12
+ * @param mixed[] $params
+ */
+function ws_images_emptyLounge($params, $service)
+{
+  include_once(PHPWG_ROOT_PATH.'admin/include/functions.php');
+
+  $ret = array('count' => empty_lounge());
+
+  return $ret;
+}
+
 /**
  * API method
  * add md5sum at photos, by block. Returns how md5sum were added and how many are remaining.