Don't break when a child is null

[davvidbaker]

It's a pretty common pattern that to do something like

<Wrapper>
  {this.state.isVisible && <Child />}
  <OtherElement />
</Wrapper>

This PR makes that possible within the <SplitPane /> component. It does this by filtering out all falsy children elements before mapping or reducing over them.

Let me know what you think, and thanks for all your hard work!

[wuweiweiwu]

Hi Thanks again for contributing!

Do you mind removing the storybook? I don't believe we currently have a storybook in place

[davvidbaker]

Do you mind removing the storybook?

For sure. Sorry for the extra commits. Stupid line at end of file kept not deleting.

[coveralls]

Coverage increased (+0.08%) to 93.548% when pulling 93d07cd on davvidbaker:v2 into 22e649c on tomkp:v2.

[wuweiweiwu]

@davvidbaker should this be based off of master instead?

Can you also do the same PR for master? :)

[davvidbaker]

Can you also do the same PR for master? :)

#307 👍