[MRG] Added metrics support for multiclass-multioutput classification

Fix for #3453 
Ping @arjoly . Added support for `zero_one_loss` and `accuracy_score`

Those new tests will trigger deprecation warnings:

```
/volatile/ogrisel/code/scikit-learn/sklearn/utils/multiclass.py:197: DeprecationWarning: Direct support for sequence of sequences multilabel representation will be unavailable from version 0.17. Use sklearn.preprocessing.MultiLabelBinarizer to convert to a label indicator representation.
```
I think we should catch that deprecation in the tests on one hand, and on the other hand we should complement those tests with new assertions that compare the outcome of the correspoding 1-hot-encoding of the same cases.

Furthermore, this error message seems to be too specific and ignore the multiclass multioutput case. I think it should be extended to tell about "multiclass multioutput" (at the risk of being harder to understand). @arjoly @mblondel @jnothman any suggestion.