gsl_matrix extension

[Øystein O Johansen]

Well, it can be easily fixed:

Untested psudo-patch:

line 42:
- double valmax = 0;
+ double valmax = gsl_matrix_get(m,0,0);

line 61:
- double valmin = 0;
+ double valmin = gsl_matrix_get(m,0,0);

-Øystein