Updating styled components and react dependencies

[leo-petrucci]

Hi,

First of all, I'm a big fan of the project, out of all the pull to refresh components I've found this was by far the best.

I've been using this in production, unfortunately, despite working without problems, the out-of-date styled-components was returning a lot of warnings and errors in my console as it was conflicting with my local installation of styled-components.

Once I specifically told webpack to use my local styled-components I started getting a lot of warning about deprecated APIs, so I decided it might be worth going directly to the source and updating the dependency.

The changes are really simple and consist mainly of updating the Styled Components in the component to their modern APIs.

Let me know if this can be merged, it would be really helpful!

[xeewi]

I could be really cool to merge this :D