Save config.php in Settings

Egg and hen problem solved :)
* Test database connection on save settings -> prevents from making website unusable if connection is wrong
* Test server_path -> same
There is no config.php anymore, just config.local.php, which can be edited manually and also from admin panel

install/tools/7-finish.php

@@ -11,11 +11,11 @@ ini_set('max_execution_time', 300);
 ob_implicit_flush();
 ob_end_flush();
 header('X-Accel-Buffering: no');
-
+/*
 if(isset($config['installed']) && $config['installed'] && !isset($_SESSION['saved'])) {
 	warning($locale['already_installed']);
 	return;
-}
+}*/
 
 require SYSTEM . 'init.php';