Adding to the list, Contour is a recent open source library that is easy to use and extensible: http://forio.com/contour/ http://forio.com/contour/ it also ha

Adding to the list, Contour is a recent open source library that is easy to use and extensible: http://forio.com/contour/ http://forio.com/contour/ it also has good documentation: http://forio.com/contour/documentation.html http://forio.com/contour/documentation.html