Invalid props on DOM elements

[aautem]

I'm currently getting warnings that React (16.2.0) does not recognize the data-ifEmpty and data-showOnlyWhen props on the buttons in the Toolbar. The warnings are requesting that the prop names be all lowercase.

I've noticed that the the repo has changed quite a bit since the last release (0.3.7) so wasn't sure if a PR for this issue would be helpful moving forward or not. Any idea when the next release will be available?

Thanks :)

[MattMcFarland]

Hi!, feel free to send a PR - I'll be happy to update that to 0.3.8 and make sure to carry it over in the new version that is still in WIP.