Use original geojson as input

[rowanwins]

This resolves the issue identified in #118 by using the original geojson where it's available rather than stuff that's been passed through leaflet.

[w8r]

But leaflet is not supposed to do anything with it, the clipping and path simplification are only done in the rendering and don't affect the initial latLngs

[rowanwins]

I does seems strange @w8r but I'm having a hard time pinning things down.

I just noticed that the codepen used the same behaviour of passing things into leaflet and then back again... so perhaps it's not what I thought...

Does the #110 set of polygons work for you when you run the demo locally?

[rowanwins]

So we could possibly close this - although I think my preference would be to still merge it and use the raw geojson rather than passing it into leaflet and back again, just seems a bit less risky.

[bluenote10]

Does that mean there is a different cause of the modified input values we have seen in #111 / comment or does this PR solve that?

[rowanwins]

There are also some lines in the current master demo site which stringify and parse the input data so that could be responsible also...

[rowanwins]

It seems like #85 is impacted by the demo site change. Works on the master branch, but not on this branch.