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[Lapack] Proposed interfaces for extra-precise refinement.

And "Xiaoye S. Li" writes:
 - *       PARAMS(ITHRESH_PARAM = 3) : Total number of residual computations
 - *            allowed for refinement.
 - *         Default: 10 for double-precision, 5 for single-precision

 - I think we have decided to remove single-precision (or working-precision)
 - refinement.  So the default should be 10 always?

Good catch, thanks.  So the default should just be 10.

(And to everyone else: We've removed working-precision 
refinement from the SGESVXX interface.  It's still in 
SGESVX (one X).)

 - For least squares refinement, it seems we will need two separate
 - ERR_BNDS arrays, one for X, another for residual R.

I believe the least-squares interface is still up in the 
air.  If we return bounds on the residual, it'll suffice 
to add two to n_norms and use those slots.  These are just
different scalings on the combined [x';r'] vector.

 - Also, there are several reciprocal condition numbers floating around:

I think we're waiting on the data to know which actually 
hold appropriate, non-redundant information.


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