Update babel dependencies

[ntaylor89]

I'm attempting to use styled-components with their babel plugin, so I can specify a css prop like so

<Box css={`some css here`} />

It appears this plugin only works with babel 7.0+ (babel will not compile syntax the css prop on any previous version), but x0's current dependencies have it locked at babel 6.

Looks like the only way to get this working with x0 would be to bump it's depencies / swap out it's babel presets.

[chrisdwheatley]

I took a stab at updating to babel 7 here #117. It'd be cool if you could give it a try and see how far you get.

[ntaylor89]

Nice! I'll take a look.