…ns when they should have been doing spherical (3D). Most changes were to nearestPointOnLine. pointToLineDistance now uses nearestPointOnLine for spherical calculations. Flow on corrections impacted lineSlice and nearestPointToLine as well.

Tidied up some tests - fixed module name in test definitions, added a benchmark overall time in a few places for easier comparisons.

…ans and toDegrees functions from turf-helpers.

…iansToDegress and degreesToRadians from turf-helpers. It seems (degrees * Math.PI) / 180 can sometimes differ slightly from degrees * (Math.PI / 180).