[whitespace] use single quotes for strings. fixes airbnb#68

Author: hshoff

README.md

@@ -783,19 +783,19 @@
         .updateCount();
 
     // bad
-    var leds = stage.selectAll('.led').data(data).enter().append("svg:svg").class('led', true)
-        .attr('width',  (radius + margin) * 2).append("svg:g")
-        .attr("transform", "translate(" + (radius + margin) + "," + (radius + margin) + ")")
+    var leds = stage.selectAll('.led').data(data).enter().append('svg:svg').class('led', true)
+        .attr('width',  (radius + margin) * 2).append('svg:g')
+        .attr('transform', 'translate(' + (radius + margin) + ',' + (radius + margin) + ')')
         .call(tron.led);
 
     // good
     var leds = stage.selectAll('.led')
         .data(data)
-      .enter().append("svg:svg")
+      .enter().append('svg:svg')
         .class('led', true)
         .attr('width',  (radius + margin) * 2)
-      .append("svg:g")
-        .attr("transform", "translate(" + (radius + margin) + "," + (radius + margin) + ")")
+      .append('svg:g')
+        .attr('transform', 'translate(' + (radius + margin) + ',' + (radius + margin) + ')')
         .call(tron.led);
     ```