- for all functions, except when GIL option (not implemented) is here
we use a triqs::py_stream, which redirect the stream
to python sys.write
- so that a simple C++ code with a std::cout
print its output in the notebook...
- NB : it only works for the code within the cell.
If it calls another function on the lib which uses cout,
print is not redirected.
Designed for simple tests....
- cerr not (yet) redirected. (useful ?).
