Error page demos

• 400 Bad Request
• 401 Unauthorized
• 403 Forbidden
• 404 Not Found
• 405 Method Not Allowed
• 406 Not Acceptable
• 408 Request Timeout
• 413 Request Entity Too Large
• 414 Request-URI Too Long
• 417 Expectation Failed
• 500 Internal Server Error
• 502 Bad Gateway
• 503 Maintenance
• 504 Bad Gateway