Workaround for presimplify bug in Chrome.
Workaround for presimplify bug in Chrome.

Fixes #192.

whoinlee/topojson,koshlan/topojson,youprofit/topojson,AlpinHologramm/topojson,studiowangfei/topojson,ongerit/topojson,mbostock/topojson,lyhpcha/topojson,btahir/topojson,ststeiger/topojson,hcxiong/topojson