SF patch [#466616] Exclude imported items from doctest,

SF patch [#466616] Exclude imported items from doctest,
from Tim Hochberg.  Also mucho fiddling to change the way doctest
determines whether a thing is a function, module or class.  Under 2.2,
this really requires the functions in inspect.py (e.g., types.ClassType
is close to meaningless now, if not outright misleading).