index fix for _value which should not include the decimal part of slice.start as the numpy slicing floors the starting index. This also fixes the max_abs_value which returned an incorrect value after using index_at_value which interpolates between two values.
Heading Excursion renamed to Variation where required and all Heading Deviation names updated appropriately
cleanup of excessive docstrings
StableApproach engine limit lowered from 55% to 45% and 8 second moving average added to vertical speed to reduce effect of peaks and troughs.
StableApproach engine limit lowered from 55% to 45% and 8 second moving average added to vertical speed to reduce effect of peaks and troughs.
Merge branch 'master' of github.com:FlightDataServices/FlightDataAnalyzer