Americas poly files revised

Fixed

anguilla.poly
antigua_and_barbuda.poly
aruba.poly
barbados.poly
bermuda.poly
british_virgin_islands.poly
cayman_islands.poly
costa_rica.poly
dominica.poly
dominican_republic.poly
el_salvador.poly
greenland.poly
grenada.poly
guadeloupe.poly
haiti.poly
jamaica.poly
martinique.poly
montserrat.poly
puerto_rico.poly
saint_vincent_and_the_grenadines.poly
trinidad_and_tobago.poly
virgin_islands_us.poly

rest will follow

Island poly were simplifed A LOT, and land borders are countries border with 10m offset for minimal overlap.