[PATCH] Use the inf-norm rather than 2-norm in issymmetric; add ishermitian.

[John W. Eaton]

On  7-Dec-2007, Jason Riedy wrote:

| I would argue that many existing programs *already* return weird
| results with no warning.  Complex symmetric is a very, very
| different beast than complex Hermitian.

| I'd be more comfortable
| seeing issymmetric removed altogether than changed to be
| isnotreallysymmetricbutwegottakeepthis.

We use it in a few spots in Octave.  As far as I can tell, they are
all for real-valued matrices, so the recent change should not cause
trouble for Octave code.  OTOH, I'm not sure it is a good idea to
change the behavior this close to releasing 3.0.

jwe