Examples in C++?

Hi, LoIK team,

Thanks for sharing the code of this amazing work! 

I wonder if you could provide a simple example script to show how to apply the LoIK algorithm in a specific robotic platform, for example, solving IK of a [four-bar linkage system](https://github.com/stack-of-tasks/pinocchio/blob/master/examples/simulation-closed-kinematic-chains.py).