Fix bug 139 submitted by Christoph Conrads on Oct 6th 2015

Fix bug 139 submitted by Christoph Conrads on Oct 6th 2015
"according to the LAPACK documentation, xSTEDC guarantees to
return the eigenvalues in ascending order (parameter D on exit). To
this end, it sorts the eigenvalues if necessary.

If there is only a single subproblem of size n, no sorting algorithm is
called (cf. {s,d}tedc.f, line 450). Furthermore, xLAED0
({s,d}tedc.f:400) does not guarantee to return eigenvalues in ascending
order. Thus, xSTEDC may return eigenvalues that are not in ascending
order."

Applied patch provided by Christoph Conrads: "always sorting the eigenvalues"