2.1.0

Now defaults to throwing an Error when a required module is not found, but this behavior can be changed by setting options.allowUnresolvedModules
options.excludeNodeModules can now be set to true or to an Array containing modules to be excluded from the project
stats.unresolvedModules contains information about modules that could not be found. Only relevant when options.allowUnresolvedModules is true.

2.0.0

Almost a complete re-write of the original project.

Supports streaming CommonJS modules to a Readable stream
Supports bundling for the browser, Node.js, and others
Added Promise support
Dropped support for Node < 4
Changed options a bit (i.e. excludeNodeModules instead of includeNodeModules)
Added options.extensions and options.compilers (see README)
Changed format of cb: now cb(err, stats) where stats exposes files included / excluded in the project build
Now depends on NPM resolve package
Fixed a few bugs
Updated docs and added a bit more complexity to the test_project

1.x

It's old now, and I'm too lazy to fill in the changelog. :)