Demo site bugs

[rowanwins]

So in investigating why we were getting different results in different spots (eg this comment here) it turns out the demo site was passing the geojson into leaflet and then using leaflets toGeoJson method the recreate the geojson being passed into the martinez operation.

I suspect this caused some mutations of the input data and is why we're getting a mismatch in the demo site vs codepen vs node etc...

So I'll open a PR for the demo site and we'll need to revisit which issues #111 actually closes for real :(

cc @w8r & @bluenote10

[rowanwins]

Turns out the codepen does this too...