4th debugging example

Try

./make_module_1.sh gridloop4

and experience

python -c import ext_gridloop; print dir(ext_gridloop); \
           print ext_gridloop.__doc__
Traceback (most recent call last):
  File "<string>", line 1, in ?
ImportError: dynamic module does not define init function (initext_gridloop)

Eventuall we got a precise error message (the initext_gridloop was not implemented)