v2.0.0

• Changed organization chuhlomin → errornil, so import github.com/errornil/mta/v2
• SubwayTimeClient renamed to FeedsClient.
• NewBusTimeClient, NewFeedsClient, NewLIRRClient now accept http.Client and User-Agent and return error along with client.
• Clients check that response status code is 200.
• BusTimeClient handles any errors returned from API (like API key is not authorized.).
• Added errors ErrAPIKeyRequired, ErrAPIKeyNotAuthorized and ErrClientRequired.
• Added unit tests.
• Fixed typo in Departures struct field name: Tranis → Trains