Update to frontend 1.5.1; fixes

vnstat_php_frontend-1.5.1:
-replaced the depreciated split() function with explode();
-renamed vnstat_php_frontend-1.5.1-updated

config.php generation:
-added two new static variables for vnstat_php_frontend-1.5.1; $locale and $language
-updated version number

// Unpack and move Vnstat frontend 
	exec("cd ..");
	exec("tar -zxovf /usr/local/pkg/vnstat_php_frontend-1.5.1-updated.tar.gz");
	exec("mv vnstat_php_frontend-1.5.1-updated /usr/local/www/vnstat2");

$locale = "\$locale = 'en_US.UTF-8';";
$language = "\$language = 'en';";

$locale
$language