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

www/configs/config.host.php

@@ -27,6 +27,8 @@ $SITE_CONFIG = array (
 		'debug_flag' => true,
 		// site language
 		'site_lang' => 'en_utf8',
+		// enable/disable login override
+		'login_enabled' => true
 	)
 );