Revert "Don't store zero weight items in foundation::CDF"
Revert "Don't store zero weight items in foundation::CDF"

This reverts commit f4c3657c5f06c1c225b5178c7e7a4847be72be02.

Vertexwahn/appleseed,pjessesco/appleseed,luisbarrancos/appleseed,appleseedhq/appleseed,dictoon/appleseed,Vertexwahn/appleseed,appleseedhq/appleseed,est77/appleseed,luisbarrancos/appleseed,pjessesco/appleseed,luisbarrancos/appleseed,appleseedhq/appleseed,dictoon/appleseed,Biart95/appleseed,est77/appleseed,appleseedhq/appleseed,est77/appleseed,luisbarrancos/appleseed,dictoon/appleseed,Vertexwahn/appleseed,est77/appleseed,pjessesco/appleseed,Biart95/appleseed,dictoon/appleseed,appleseedhq/appleseed,Vertexwahn/appleseed,Vertexwahn/appleseed,Biart95/appleseed,est77/appleseed,pjessesco/appleseed,pjessesco/appleseed,dictoon/appleseed,luisbarrancos/appleseed,Biart95/appleseed,Biart95/appleseed