October, 2016: This project is in hiatus: There is already a plethora of frameworks to choose from and the author is too busy persuing other things. Updates to the specification are still being made, and one should never rule out that the author may have a change of heart (or, more likely, professional needs) and implement some (or even most) parts, however slim the chance may seem.
Would you like to see previous stable implementation? Try this branch.