[ODE] plane2d and heightfield examples

[Bram Stolk]

dHello()

The new plane2d and heightfield examples were broken on double precision builds.
I've just committed a fix.

One snag: the sources were in SVN with ^M chars in it.
My fixed version contains no ^M, so the diffs are unreadable.
Do we have a policy on ^M ?

About the fix:
Basically, it comes down to using two different draw funcs from ds:
dDrawBox versus dDrawBoxD

   Bram