title: time scale displays wrong year
body: <p>I'm trying to display a timescale axis with only years as tick labels but the year displayed is wrong. With the sample code below it shows as : "1951  1952  1953  1953  1954". It looks like a roundoff error as if you show the month it switches from January to December: "Jan-1951  Jan-1952  Jan-1953  Dec-1953  Dec 1954..."</p>
  
  <pre><code>var svgContainer = d3.select("body").append("svg")
                                      .attr("width", 3000)
                                      .attr("height", 300);
  
  var axisScale = d3.time.scale()
                    .domain([new Date("1950-11-11"), new Date("1980-07-14")])
                    .range([0, 3000])
                    .nice(d3.time.year);
  
  var xAxis = d3.svg.axis()
                .scale(axisScale)
                .ticks(d3.time.year, 1)
                .tickFormat(d3.time.format("%Y"));
  
  svgContainer.append("g").call(xAxis);
  </code></pre>
  
  <p><strong>Update</strong>: The bug only shows in Firefox (see <a href="http://imgur.com/oQfHE7D" rel="nofollow">http://imgur.com/oQfHE7D</a>). So it's probably down to JS implementation differences.</p>