Add the ability to load data with colors

src/api.load.js

@@ -20,6 +20,12 @@ c3_chart_fn.load = function (args) {
             config.data_axes[id] = args.axes[id];
         });
     }
+    // update colors if exists
+    if ('colors' in args) {
+        Object.keys(args.colors).forEach(function (id) {
+            config.data_colors[id] = args.colors[id];
+        });
+    }
     // use cache if exists
     if ('cacheIds' in args && $$.hasCaches(args.cacheIds)) {
         $$.load($$.getCaches(args.cacheIds), args.done);