Talos humanoid performing a sine task

This PR adds the Talos humanoid model example. In this example the Talos robot performances a sine task in the trunk position. Preliminary results produces undesired motions on the upper body. First I tried to add a SO3 regularization in the torso, the torso motion was much better but the arm ones were still undesired. This includes the development of SO3 cost function with their unit-test code. Second, I tried a simpler approach based on the posture regularization. This is the one that I am committing here.

This PR tackles the task #23 (closed).

Note that this is another example that helps us to devise a better DDP solver, and users to learn from scratch how to use this library. @kgiraude @ostasse you might be interesting in this commit.