Updates to Steady state module

- Return profile reduction ratio in debug mode when using RCM.
This is kind of nice to have before the calculation is done, just to 
gauge the benefits of reordering. I am still puzzled as to all the work 
on the logging module, but I will take a look at it.

Robert Johansson wrote:
>
> In qutip/steadystate.py:
>
> > print('RCM bandwidth:', rcm_band)
> > print('Bandwidth reduction factor:', round(
> > old_band/rcm_band, 1))
> > + print('Profile reduction factor:', round(
>
> Here we could consider using the new qutip.logger module instead of
> print calls, or even putting this information in
> ss_args['return_info'] instead of (or in addition to) printing it. But
> this can obviously wait until some other day,
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/qutip/qutip/pull/250/files#r20554943>.