[ODE] Just Documented some Universal Joint Functions

[Martin C. Martin]

Hi All,

Last October, John Buehler mentioned some undocumented functions:

I noticed that there are four functions for Universal Joint support that are
not documented:

dJointGetUniversalAngle1
dJointGetUniversalAngle2
dJointGetUniversalAngle1Rate
dJointGetUniversalAngle2Rate

I'm sure all developers using ODE would appreciate a mention of these
functions in the documentation.

JB

I just added some simple documentation and committed it.

Enjoy,
Martin