A Perl Port, README (Polygons) and test.js

[aavmurphy]

A Perl port

https://github.com/aavmurphy/CheapRuler
https://metacpan.org/pod/Geo::CheapRuler

Some clarification on polygons. Is this correct?
Polygons are a series of rings.
The first ring is exterior and clockwise.
Subsequent rings are interior (holes) and anticlockwise.
Do the first and last point of each ring have to be the same?

In test.js, in lineslice and lineslicealong, i needed to add
const clean_line = turf.cleanCoords( turf.lineString(line) );

(this removes duplicate adjacent points)

Thank you for CheapRuler!
Andrew