Update x-labels without full redraw

Author: aaronhayes

.gitignore

@@ -30,3 +30,5 @@ node_modules
 .DS_Store
 showcase
 .generator-release
+
+.idea/*

lib/core.js

@@ -42,6 +42,7 @@ module.exports = {
       } else {
         dataKey = dataKey || dataKeys[chart.name];
         updatePoints(nextProps, chart, dataKey);
+        chart.scale.xLabels = nextProps.data.labels;
         chart.update();
       }
     };