Add a FaustAlgoGen pyx class to enhance the genericity of the python wrappers...

Add a FaustAlgoGen pyx class to enhance the genericity of the python wrappers (no code duplicates for complex and double).

pyfaust.wht received new argument dtype to generate a Hadamard transform as a complex Faust. Adjusting the C++ code for this to work.

_FaustAlgoCplxDbl.Pyx: is for functions that only exist for complex Fausts (dft).