Bug fix for translation class, DB IO connection error set fix

- The translation file reader did an isset on a set variable insetad of
checking if the variable is zero and so never started the translation
system
- The DB IO connection not set was wrongly set. If the connection failed
it is not TRUE and else FALSE. There is a new internal method
getConnectionStatus to query this status it returns TRUE/FALSE depending
if the connection failed

- Update the l10n test page with proper translation tests
  - init OK
  - show current lang/file
  - translation test
  - switch language test

.phan/config.php

@@ -95,6 +95,7 @@ return [
 		 'www/media',
 	],
 	'exclude_file_list' => [
+		// ignore all symlink files to edit
 		'www/admin/edit_access.php',
 		'www/admin/edit_groups.php',
 		'www/admin/edit_languages.php',