A brick apply can call another apply of this brick
Wrapping to respect hierarchy

When a recurrent apply method is wrapped one has to define a wrapper
of initialization method and include it in the signature.
Refactoring of Readouts
PEP8
Softmax, lookup, updates handling
Fix bug in SoftmaxEmitter
More updates handling
Markov Chain generation case study
Some smart naming of inputs and outputs
`properties` to become a real attribute