Introduce class pyfaust.factparams.ConstraintList in the ongoing effort to...

Introduce class pyfaust.factparams.ConstraintList in the ongoing effort to simplify facto. algorithm parametrization.

The inference rules on dimension sizes are not yet implemented.
Updating examples for fact_hierarchical() and fact_palm4msa() to use ConstraintList.

Also a minor typo. into test_FaustPy.py