Added semicolons for javascript coding consistency.
Re-appended first coordinate before geometry simplification.

If it isn't already identical to the last one, that is. utils/simplify pretty
much expects closed polys. I encountered a couple of those, that are not, and
there seems to be no regulation about it (QGIS accepts both for instance).
Re-appended last coord in _list/export.

Now that I've actually read the GeoJSON specification, I realized that
LinearRings (as they say) are pretty much mandatory.