This is an example (and test) of using swig generated modules in the context
of python3's namespace packages:
https://www.python.org/dev/peps/pep-0420/
Consequently, this example requires python (3.3 or newer) to build and run.
This example creates a simple swig module named robin. The robin.py module
has a companion C module named _robin.so. The robin module is tested in four
ways:
1) As a non-package module (tested by nonpkg.py)
2) With robin.py and _robin.so in the brave package under the path1
subdirectory. (tested by normal.py)
3) With robin.py in path2/brave and _robin.so in path3/brave
(tested by split.py)
4) With robin.py contained in a zip file (path4.zip) as brave/robin.py and
_robin.so found on the filesystem under path3/brave (tested by zipsplit.py)
Note: Using namespace packages with subpackages (such as brave.sir.robin) where
robin.py is located in a zipfile requires python-3.5.1 or newer as
python's zipimporter only worked with packages of depth 1 until then.
