prep this repo to be consumed by other repos

[laurengarcia]

a few things in preparation for publishing this repo via npm modules:

• separated styleguide.css from base.css (base.css will be the base styles for dat design -- changed from main.css since i'm imagining other modules may already contain main.css). this way other devs can include base.css without getting the cruft of the styleguide.css, too.
• added "keyword" property css-module to package.json so when we publish this as an npm module, it will be discovered by http://cssmodul.es/
• added "style" property to package.json for compatibility with rework-npm or npm-css imports: https://www.npmjs.com/package/rework-npm https://www.npmjs.com/package/npm-css
• created an index.js that will export each css file to other projects if they wish to import .css that way via their own cli/build tools

am just going to go ahead and merge this PR real quick so i can go see how best to import this via npm to other projects. if there's anything that's amiss here, we can revisit later. am just documenting changes in this PR for other folks' benefit.

[okdistribute]

Awesome cool!

[laurengarcia]

It's happening!

[max-mapper]

nice, that escalated quickly!

[laurengarcia]

hehe -- yeah, this could get wayyy out of hand: https://github.com/reworkcss/rework/blob/master/Readme.md#plugins

[Kriesse]

Whoo, thanks a bunch (and in particular for documenting this in detail here, super helpful for me)!!