WIP: Add comments about vars usage at instantiation.
WIP: name change override_meth -> numpy_ufunc.
WIP: Fix memory leak of normal_args and normal_kwds.
WIP: Add comment. continue -> break.

While checking for sub-types to the right of obj. We can break when one
is found instead of continuing to scan the rest of the args.
WIP: Change control of finding overriding arg as suggested by @pv.
WIP: Move override_obj = NULL statement.
WIP: Change control flow as suggested by @pv.

This addresses the following comments:
https://github.com/numpy/numpy/pull/3524/files#r5665109
https://github.com/numpy/numpy/pull/3524/files#r5665218