Add the option to add a special class to datapoints

[JelteF]

This way you can style them differently, like making the label bold or a different color. Or make some bar more visible than others.

[sudodoki]

I can tell there's odd change in gruntfile. As to API I would suggest adding classFor callback

[JelteF]

Oh, stupid mistake. I added that for testing myself. And I'll look into the callback, think I've missed that one

[sudodoki]

There's none, just a suggestion to what this feature might look like: classFor callback in your options.

[JelteF]

I changed it to a callback named barClass to have the same type of interface as the barColors callback.