Use namespace import instead of default import for React

[CruseCtrl]

I don't have allowSyntheticDefaultImports set in my project, so the typescript compiler is giving me warnings about these imports. This PR will fix the warnings

[fkhadra]

Hey, why not enable allowSyntheticDefaultImports in your config?

[CruseCtrl]

That's what I've been forced to do for now, but it would be nice if it wasn't necessary for all users of this library to have to turn on that compiler flag, and it's a very easy fix to just import it correctly