[ODE] Implementing genuine Coulomb friction

[Gary R. Van Sickle]

> Also, if there is a way in the latter case, should I have any sort of
> confidence that either my working with the internals of ODE will not
> break when a later version comes out, or even better, that it is
> unlikely that a later version will break whatever I end up doing
> without additionally implementing a correct means to a full cone
> based implementation of friction?
>

Why not make sure that's the case and contribute the code?  Make it selectable
somehow, and I can't see why Russ wouldn't accept it.

--
Gary R. Van Sickle
Brewer.  Patriot.