toMercator changes polygons geometry

When using toMercator on a polygon that overlap the -180 or 180 longitude, without antimeridian cutting.

The current implementation wraps every point one by one which ends up returning a wrong polygon:

Here is a polygon overlapping the -180 longitude:

• https://gist.github.com/Darune/d73952fbe586d1e8116d6e779042ccb3 Here is the result of a toMercator transformation reconverted using toWgs84:
• https://gist.github.com/Darune/dbd604f5b697cbbd36b918acab2dea94

code to reproduce the issue:

import { toWgs84, toMercator } from '@turf/projection';

toWgs84(toMercator({
  "type": "Feature",
  "properties": {}, 
  "geometry": {
    "type": "Polygon",
    "coordinates": [[
        [-181, 60],
        [-181, 61],
        [-179, 61],
        [-179, 60],
        [-181, 60]
    ]]
  }
}));

I think that when calling toMercator with a GeoJson, turf should not try to wrap longitude as it does. if this is an acceptable behavior I could submit a PR

[Darune]

I could retry writing tests for this, it has been stalled for way too long, but I might have time next week to digg this out of the dirt

[rowanwins]

Yeah unfortunately the tests and the code are currently setup to run against individual coordinates rather than seeing them in context of a geometry that is crossing the anti-median, so a bit of thought needs to happen to get things behaving and tested properly.