Publish JSX to npm

I made a few changes so that you can publish JSX to NPM (please do). This pull request does the following changes:

* The embedded `node_modules` folder is removed in favor of fixed dependencies in the `package.json` file. This results in a much leaner package.
* An `.npmignore` file is added so that tests and other unnecessary development stuff does not get published to NPM.
* Minor changes to the README to account for the changes.

Basically, the following guide was followed: https://npmjs.org/doc/developers.html

What you need to do:

* Merge this pull request
* Increase the version number in `package.json` (0.1.0 is common for initial NPM releases) and commit+push the changes
* Create an NPM user for yourself with `npm adduser`
* Publish the package with `npm publish`

All that should only take 5mins or less. Then you will be able to do npm install jsx -g, or use jsx as a dependency in your own package.json file:

    "dependencies": {
      "jsx": "0.1.0"
    },

And you no longer have to worry about everyone having different versions of JSX!

If you want to update the package, just do your changes, increase the version number and publish again.

I have been using JSX as an NPM module for about one week, and there have been no problems (especially considering the low, low version of 0.0.2).