title: topojson.object in topojson V1
body: <p>I am having a lot of fun playing with topojson, but it looks like topojson.object is undefined in V1 of topojson, where it was supported in V0.  Can someone explain how I might work around this issue?  I am trying to draw distinct path elements for each polygon in an input file formatted as topojson.  the code is:</p>
  
  <pre><code>d3.json("maTopo.json", function(error, ma) {
      svg.selectAll(".subunit")
        .data(topojson.object(ma, ma.objects.ma).geometries)
      .enter().append("path")
        .attr("class", function(d) { return "subunit " + d.id; })
        .attr("d", path);
  });
  </code></pre>