Expose color

src/echarts.js

@@ -1307,6 +1307,7 @@ define(function (require) {
     echarts.format = require('./util/format');
     echarts.matrix = require('zrender/core/matrix');
     echarts.vector = require('zrender/core/vector');
+    echarts.color = require('zrender/core/color');
 
     echarts.util = {};
     each([

src/visual/seriesColor.js

@@ -20,6 +20,7 @@ define(function (require) {
                     });
                 }
 
+                // itemStyle in each data item
                 data.each(function (idx) {
                     var itemModel = data.getItemModel(idx);
                     var color = itemModel.get(colorAccessPath, true);