/*! \page python Python wrapping


The main classes and methods are wrapped in Python with 
the SWIG tool (at least version 1.3.24)

\section python_modules Multi modules
As in C++ the wrapping is split in 3 modules : engine, runtime, loader
so that other runtime or loader can be used with the same engine.
We need to be careful with definitions shared by the 3 modules : put
them in a unique dynamic library and link the modules with it.

\section python_exception Exception wrapping
In swig, exception can be wrapped either by declaring throw in interface
file (.i) or by declaring an exception handler.
A generic exception handler has been declared and automatic generation has been 
desactivated (SWIG option -noexcept).

\section python_gil Global Interpreter Lock
For some methods we need to release the Python GIL.
This is done by using a swig exception handler that releases the lock
on entry and reacquires it on exit. 

\section python_ownership Ownership
Some methods (factory mainly) don't give ownership to python. For example,
createNode from runtime object returns a newly created node to python but
python has not ownership so when it disappears from python, the C++ object
is not destroyed.
To give ownership to python we use %newobject macro.

*/