Only one import of the low-level C/C++ module from the pure Python module is
attempted now. Previously a second import of the low-level C/C++ module was attempted
after an ImportError occurred and was done to support 'split modules'. A 'split module' is
a configuration where the pure Python module is a module within a Python package and the
low-level C/C++ module is a global Python module. Now a 'split module' configuration is
no longer supported by default. This configuration can be supported with a simple
customization, such as:
%module(package="mypackage", moduleimport="import $module") foo
or if using -builtin:
%module(package="mypackage", moduleimport="from $module import *") foo
instead of
%module(package="mypackage") foo
See the updated Python chapter titled "Location of modules" in the documentation.
Closes#848#1343
