Fix problem with tuning 100% chart

src/axis.js

@@ -377,7 +377,7 @@ c3_chart_internal_fn.tuneAxis = function(sync, callback){
     $$.pushCallback(callback);
 
     // if we don't need to tune
-    if($$.config.stacked){
+    if($$.config.normalized){
         $$.cachedRedraw();
         return;
     }

src/config.js

@@ -57,6 +57,7 @@ c3_chart_internal_fn.getDefaultConfig = function () {
         data_columns: undefined,
         data_mimeType: undefined,
         data_keys: undefined,
+        normalized: false,
         // configuration for no plot-able data supplied.
         data_empty_label_text: "",
         // subchart