Supports package manager such as browserify, cortex, etc

Phaser is really awesome, making it super easy to create a game using few lines of code.

- adds .npmignore files to ignore the files which are for development and not needed by npm, so that the tarball(.tgz file) will not be so big and users could download phaser much faster.
- adds a `main` field in package.json, so that phaser could be installed by [browserify](https://github.com/substack/node-browserify) or [cortex](http://ctx.io).
- npm on longer allow uppercased package name, so I rename it as a lowercased one.