Heavy delay with a bar graph after 14 bars added

* **C3 version**: 0.4.18
* **D3 version**: 4.12
* **Browser**: Chrome, Firefox
* **OS**: Windows 10

[gitHub.zip](https://github.com/c3js/c3/files/1511602/gitHub.zip)

Hello, I'm working on a project for my class. I am displaying video game data via a chart. I've tried a few other platforms, but chose this one based on a more complete documentation than others. I've gotten a working prototype running, but noticed a slight delay in updating the chart after 8 selected items, and a much more significant delay after 14. Beyond that there are heavy heavy delays up to 20 seconds. I've attached my project to demonstrate, sorry I couldn't work out something more simple.

Is this inevitable with c3js? Or is there something I can do to remedy the lag?

Thanks, Ryan