Fixes for Speedbrake KPVs. runs_of_ones fixed for masked arrays.

runs_of_ones_array renamed to runs_of_ones and now returns slices and does not return sections of masked data. Speedbrake KPVs updated to use the new version of the function and tests added. Added frequency to create_kpvs_from_slice_durations for the implementation to match the docstring. Added filter_slice_duration which also takes frequency into account.
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer