Fix failing test.
Fix failing test.

The failing test contained two polygons, one with a CW and the other
with an equivalent but CCW ring, and each with a zero-area ring.  The
rings for both polygons are now automatically reordered so that the
zero-area rings are treated as holes.  The non-zero-area rings are
forced to be clockwise, since they are both exterior rings.  Finally,
the zero-area rings are removed by filter, resulting in both polygons
having the same clockwise ring.

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