Consequence the AdaoExchangeLayer instance should NOT be surrounded by GIL protection.
+Consequence : AdaoExchangeLayer::initPythonIfNeeded initializes the python interpretor (if not already done) and let the GIL released to manage all python caller threads easily
+
+Consequence : Using ADAO interface implies to protect python calls
+
############## user GIL management in AdaoModel::MainModel
The custom MainModel overloading should be GIL protected by the user.
