Renamed Test.cs to StopsAndRoutesTest.cs
Implemented Alerts API (Services part WIP)

* Added test case TestAlertsGetAlertsSuccess when no access
  and no service alerts are being requested
* Added test case TestAlertsGetAlertsSuccess when access requests
  but no service alerts are being requested
* Implemented Data types Alert, AffectedServices, Elevator,
  ElevatorStop, ElevatorType, EffectPeriod, AlertSeverity
  and AlertLifecycle