Fix for delta encoding.
Fix for delta encoding.

btahir/topojson,tsl3su/WorldMap_Choropleth,mbostock/topojson,maxogden/topojson,koshlan/topojson,lyhpcha/topojson,youprofit/topojson,sgillies/topojson,hcxiong/topojson,studiowangfei/topojson,ongerit/topojson,whoinlee/topojson,AlpinHologramm/topojson,ststeiger/topojson,sgillies/topojson