This finishes the effort to port python-wrapper.swig code over to
using PythonDataObjects.
Also included in this patch is the removal of `PyCallable` from
`python-wrapper.swig`, as it is no longer used after having been
replaced by `PythonCallable` everywhere.
There might be additional cleanup as followup patches, but it should
be all fairly simple and minor.
llvm-svn: 252939