The latest version (1.0.3) has newly added documentation. Namely references to the open source project Box2d that I meant to have in before the first release. The @since and @version tags were also added so that differences in API versions are documented.
As a side note, performance was improved slightly by a few code changes in a hot spot method on the Polygon class called getFarthestPoint. This yielded a double digit FPS increase in the TestBed on the Bucket test.
The next phase of the project is to improve the ContactConstraintSolver. Box2d has a nice feature of a blockwise solver for contact manifolds with 2 points (since 2D only has 1 or 2 points in contact manifold). This could allow for much more stable stacking.
Along with this I have plans to create some tutorials on the methods used to create joints on by blog. Beware as it will contain a good bit of math.