Added documentation for scaled identity
Added documentation for scaled identity

I added more documentation for the scaled identity Hessian
approximation.  Basically, we should use this approximation and not the
identity when doing steepest-descent trust region since this one forces
the iterate into the trust-region boundary.

OptimoJoe/Optizelle,OptimoJoe/Optizelle,OptimoJoe/Optizelle,OptimoJoe/Optizelle