mbostock/d3 — pull request #1559 by jasondavies (2013-10-03 15:58:40+00:00)
Title: Preserve polygon exterior/interior ring ordering.

According to GeoJSON, the first ring in a polygon should be the
exterior, and subsequent rings should be holes that are inside the
exterior ring. This fix ensures that the rejoining of clipped segments
preserves these semantics, by generating multiple polygons if necessary
rather than generating all rings within a single polygon as it did
previously.

Fixes #1558.