Missing block jacobian info in python binding

[bleyerj]

When inspecting the behaviour object in Python, there seems to be no information about the block structure of the jacobian

[thelfer]

The tangent operator blocks are now available in the python bindings under the tangent_operator_blocks property of the Behaviour class.

Those blocks are accessible as an array of tuples of instances of the Variable class.

This feature can be used as follows:

import mgis.behaviour as mgis_bv

h = mgis_bv.Hypothesis.Tridimensional
b = mgis_bv.load('src/libBehaviour.so','StationaryHeatTransfer2',h)
for t in b.tangent_operator_blocks:
    print('d{}_d{}'.format(t[0].name,t[1].name))