Npm ready

See #1.

The Node.js version is generated in `node_dist/cssParser.js`. This directory is not versioned.

__Some remarks:__

I put your email in package.json, but I’ve seen that you are using the `xxx at yyy dot zzz` form. Tell me if you want to remove that email.

I added an example/ directory, I think it can be useful, but it can be removed if you want to.

The README has been updated using the project website, tell me if there is a problem with that.

The Makefile is now based on file targets, and a `clean` target has been added. I think it’s easier to work with (it only compiles the needed files), but it can be reverted if you want to (you can still force the dependency download etc. with `make -B`).

I haven’t found any version, so I put `0.1.0` in the package.json… tell me if it’s not correct.

The generated cssParser.js does not correspond to the previous one, I don’t know if it’s normal. See https://github.com/bpierre/jscssp/commit/b3c1d1049e1151ef7ea3401ad2a042de7320b392

__npm publication__

In order to publish the script on npm, you need to:

- Install Node.js
- Create an account on the npm registry with [`npm adduser`](https://www.npmjs.org/doc/cli/npm-adduser.html)
- Launch [`npm publish`](https://www.npmjs.org/doc/cli/npm-publish.html) in the project directory