Breaking API changes:
	- Replaced `options.includeNodeModules` with `options.excludeNodeModules`
		(defaults to including modules from node_modules)
	- `options.outputFile` is now optional when using the stream API
	- `cb` is of the form `cb(err, stats)` where `stats` is an Object
		containing `files` and `addonsExcluded` properties. (see README)
	- Added Readable stream API
	- Dropped support for Node < 4
Depends on `resolve` module instead of using a hack for `require.resolve`
Now supports `browser` flag to concatenate a project for the browser.  This
	feature reads the `browser` field instead of the `main` field in the
	`package.json` file of an included module to determine which file to
	include in the build.
Updated README doc.
Updated test_project
Fixed a bug in `header.js` so that `require.main` is properly set
Push to 2.0.0-beta