flight_leg: add missing stop_codes attribute

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>
resource: optimize the response parsing code

This is especially necessary for very large responses,
such as the flight responses from the Schedules/Connections API.

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>
version: bump version to 0.3.0

Signed-off-by: diditclear <didyourupgradeclear@gmail.com>