Chart does not re-render when dataSource is updated

[joelmukuthu]

Hi, thanks for this module. I tried live-updating the data but it doesn't seem to work. I've traced it down and found that isDataSourceUpdated doesn't detect changes in the data.

It seems to me that that method could be simplified to compare the values of dataSource._data instead of the whole object. I can send a PR for that if you think that's the way to go? Otherwise let me know if I can help debug/reproduce this.

Thanks, Joel