created Combined Climb and Descent phases as they are used in multiple places to ensure climb KPV's are created in climb and descent KPV's in descents
amended create_ktis_on_state_change  to prevent creation of KTI's imediatly following large sections of masked data
Rate of descent KPV's changes to limit KPV creation to descent phases of flight
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer