[ODE] unstable objects and the documentation

[DjArcas]

> > Regarding stable simulations. What is the recommended size/density/mass
of
> > objects?
>
> I suggest using realistic values for starters.  Then, if you have
> problems, go back and tinker with the values and see how much that
> helps.  Tell us what you find. :-)

I'm pretty sure I am using realistic values. My scale is roughly the same as
that of the test buggy - 0.7 long, 0.5 wide, 0.2 high... That'd make 1 unit
= 10 metres(or possibly a bit less than). Or this really is a match box
sized car in test_buggy! :)