Fixed spelling mistake

Wiener not Weiner!

Signed-off-by: Andrew D. Horchler <adh9@case.edu>
Support for Output Function added to SDE options

Output functions only supported for sde_euler() and sde_milstein() currently. Also passing of integrated Wiener increments to output function not implemented and may cause errors if used. an SDEPLOT, a version of ODEPLOT, is in the works.

Signed-off-by: Andrew D. Horchler <adh9@case.edu>
Demo folder and three new simple SDETools demos

These demos are preliminary. They may change significantly, be removed, or be replaced by others at any point. I may put a demo folder in the toolbox folder directly eventually.

Signed-off-by: Andrew D. Horchler <adh9@case.edu>