extending tauEncoding given list to retrive topo_sub even if a line i…

[marota]

…s disconnected

Related to this issue #11

[BDonnot]

Job is done in the next PR

[marota]

@BDonnot Current code doesn't disregard disconnected lines in all cases.
The following test currently fails when one line is disconnected from bus bar 1 and one line is disconnected from bus bar 2

       #test for 2 line disconnections: one on bus bar 1 and one on bus bar 2
        obs = env.reset()
        indices_sub_1=range(proxy.subs_index[1][0],proxy.subs_index[1][1])
        obs.topo_vect[indices_sub_1]=[2, 1, 2, 1, -1, - 1]
        #act = env.action_space({"set_bus": {"substations_id": [(1, (2, 1, 2, 2, -1, - 1))]}})  # (2, 1, 2, 2, 1, 1)
        #obs, reward, done, info = env.step(act) #simulation is diverging so just modifying the obs directly
        res = proxy.topo_vect_handler(obs)
        assert np.sum(res) == 1
        assert res[6] == 1.

On my side, this test fails on the current code, but succeeds with the less optimized code initially proposed in the PR