[ODE] Cylinder support

[David Walters]

"It will add a '--with-cylinder' configure flags, that
enables cylinder support."

This reminds me of something slightly trivial, I discovered that
dCYLINDER_ENABLED is not actually used by any of the code.

Would it make sense to remove this option from the build system?
having it there does kind of imply that you might not want the feature
- which is somewhat misleading since it's not really a special case
anymore.

I sort of understand not wanting tri-meshes as it involves bolting on
OPCODE, but am I right in thinking this optional cylinder flag should
stay away?

Regards,
Dave