Publish Pure via NPM

[jamesalley]

For this PR I have run npm init on Pure's package.json and then made a few edits (such as changing the name from "pure" to "purecss") so that we will be able to publish the build files to NPM. I've also added an .npmignore file so that only the build folder will be published.

Once published to NPM, the "purecss" NPM package will differ from the previous purecss NPM package in the following ways:

1. All the .css files will be in the package's /build folder instead of in root.
2. The version will have changed, of course.

Anyone who's been using npm to drop Pure into their project will have to adapt to this slight change in directory structure.

[yahoocla]

CLA is valid!

[ericf]

Prepublish script to run the build? So we don't ever publish a stale build.

[okuryu]

I like the whitelist by using the files field in package.json instead of using .npmignore file. .npmignore is blacklist, so it's not able to do unkown stuff handling.

[ericf]

Looking good. @jamesalley it's up to you on @okuryu's suggestion.

After merging this, you can update the version locally to 0.6.0-test-1 and trying publishing. If it looks good, then we can do it for real.

@tivac any thoughts on this? Specifically all the files being in build/ instead of using the pure-release repo like @undoZen did in the past…

[tivac]

👍x💯

Very excited for updated purecss NPM package.

As for the somewhat-breaking change...

394 downloads in the last month

I'm responsible for at least 20 of those, so I think you're probably ok!

[jamesalley]

I have noticed one side effect: pure-min.css becomes purecss-min.css because of the name change in package.json.