Refactor UbloxGPSSensorController into a few smaller classes

- New UbloxGPSSensor class reads serial port and builds NMEA sentences.
- New NMEASentence Parser is an abstract class which parses NMEA
  sentences into data which we can use.
- UbloxGPSSensorController now just handles and returns the necessary
  sensor data.
- If for some reason the sensor cannot be read,
  UbloxGPSSensorController.getCurrentData() will now throw
  SensorReadFailedException.