merge -c2880 from trunk to branch 2.0

- Add fetchRemote function which allow to retrieve datas over HTTP protocol using cURL method, file_get_contents function or fsockopen method. This allow to retrieve datas or files even if allow_url_fopen is deactivated.
- Use fetchRemote function in plugins manager and in latest version checking.
- Add german translations for upgrade.lang.php.
- Remove empty line at the end of pclzip.lib.php.
- Change display of deactivated plugins after upgrade.

git-svn-id: http://piwigo.org/svn/branches/2.0@2881 68402e56-0260-453c-a942-63ccdbb3a9ee

admin/include/functions_upgrade.php

@@ -127,7 +127,7 @@ WHERE id IN ("' . implode('","', $plugins) . '")
     mysql_query($query);
 
     array_push($page['infos'],
-      l10n('deactivated plugins') . '<pre>' . implode(', ', $plugins) . '</pre>');
+      l10n('deactivated plugins').'<br /><br /><i>'.implode(', ', $plugins).'</i><br />');
   }
 }