ArrayWrapper and MatrixWrapper classes should not be nested by reference.
Fix bug 791: infinite loop in JacobiSVD in the presence of NaN.
Add one more regression test for bug 791.
mat/=scalar was transformed into mat*=(1/scalar) thus laking accuracy. This was also inconsistent with mat = mat/scalar.
Improve further the accuracy of JacobiSVD wrt under/overflow while improving speed for small matrices (hypot is very slow).