circuit.parameters_ and circuit.conf_ attributes not referenced in documentation

[mathew9710]

First of all, thanks for creating this excellent tool.

I had the exact same issue as @kmylrea (described in issue #285 )

The confusion arises from the fact that attribute circuit.parameters_ is not explicitly referenced anywhere I've looked inside the documentation, unless you go digging in the source code of the circuit class.

So it would be nice (and time saving) if there was a reference to this attribute explicitly in the 'Circuits' page of the documentation as a way to obtain fit parameters as an iterable and not just as a console output as in print(circuit) option referenced in the examples.

The same happens with circuit.conf_ , not listed nor explained anywhere in the documentation unless you dig into the source.