Declutter Object ancestry

Previous method *always* added a module to the ancestry of Object in
order to get globally-available Sparsify() and Unsparsify() methods,
but the clutter made inspecting object ancestry in general more noisy
than it needed to be. Since Kernel is included into Object, define
the helper methods there instead.
Add documentation for Kernel methods
Merge branch 'declutter-object-ancestry' into develop