Updates to SS module

- Restructure code to avoid multiple copies of code snippets.
- Optionally return dict with details on solution and solver details.
- Allow for building preconditioner separately so that different
iterative methods can be applied.
- Calculates inf-norm of residual at output.
- Returns number of iterations performed.
- Allow for inputing initial guess vector.
- Calculate a lower bound on the condition number of a preconditioner.
- Residual norm is given when iterative method fails to converge.
- Removed bicg method since it is not compatible.
- General docstring edits.
- Add tests for bicgstab method.
There is no weighting factor for the power or eigen methods so I removed it
from the output info dict.
On Aug 28, 2014 2:54 PM, "Robert Johansson" <notifications@github.com>
wrote:

> In qutip/steadystate.py:
>
> > @@ -477,10 +608,12 @@ def _steadystate_power(L, ss_args):
> >      """
> >      Inverse power method for steady state solving.
> >      """
> > +    ss_args['info'].pop('weight', None)
>
> del ss_args['info']['weight']
>
> ?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/qutip/qutip/pull/221/files#r16822233>.
>