Dark versions for use on white websites

[benkaiser]

Hi @SamHerbert ,

I've forked your repository and am looking to include dark versions (#fff replaced with #000) for all the svg files, as these work great on webpages with white or lighter backgrounds (like the one I am working on right now).

If you would like, I can submit a pull request for this and maybe even include a switch on the index.html page to flip to dark versions so users are aware they exist. What do you think?

I know it's kind of duplicating things unnecessarily, but it would be really handy for the bower users out there.

If you aren't happy with that I can create a bash script that 'builds' the dark versions by taking the white version, using something like sed and replacing #FFF with #000 in them so when you make changes to the white versions you can simply run the script to build/update the dark versions.

[atlanteavila]

Why wouldn't you just add this as a prop? Seems kind of obvious to build something like this where the colors are configurable. The svg stroke should be updatable IMO.