[ODE] ODE 1.0 gyroscopic terms

[Morgan McGuire]

> I don't mind this being an option but I think it's important that a  
> physics simulation try to be as realistic as possible by default.  
> People who turn off bits of reality need to know what they are doing  
> and naive uses should expect physics to be preserved as much as  
> reasonably possible.

I'm sympathetic to your point.  ODE isn't particularly realistic, however, and
the terms I'm proposing allowing an easy way to disable (see the following
e-mail) tend to cause more unrealistic behavior than they prevent.

-m