find_edges: Will not raise for small slices

It is possible that this algorithm will be used for very brief slices of
data. It can be argued that there are no edges within an array of length
0 or 1.
geo-locate: Fix for masked Lat/Lon Smoothed

The parameter is entirely masked when the takeoff and landing runway
can't be found with the API.
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer