Add joint axes visualization

[VDB-Bram]

I am working on determining functional axes in the foot. After having determined these axes it very handy to visualize them together with the OpenSim model. Since in the regular OpenSim GUI it is not possible to display this axis, I currently use a workaround: add a wrapping surface as a proxy for the axis. This is ok to do since it is just for visualization purposes (see picture). Adding this proxy needs to happen manually, so it can take some time when having to visualize multiple axes or multiple iterations of the functional axis estimate.

Conceptually I think it would not be too difficult to implement this. What do you think? Since I am not too familiar with C++ I haven't tried myself.

I would think a button like Show joint axes or the likes would be really helpful. Or maybe this is already possible but I haven't found this feature yet?