Use optimizer for planning backflip trajectory

[jviereck]

At this point, it is not possible to optimize a backflip motion with the optimizer on the solo robot.

This issue is about tracking the required modifications / extensions to the optimizer to make this possible.

[jviereck]

Some points include:

• better endeffector trajectory planning
• have ability to specify desired base angle in the inverse kinematics along the trajectory

[majidkhadiv]

This is true, I will try to implement more delicate (while yet dynamic) motions, e. g. backflip and jumping on the box, using kino-dyn planner. But I think it needs a huge amount of work in terms of landing control and dynamically-consistent end-effector trajectory generation. I have some ideas to do that, but let's see how much time this will take... I will be devoting most of my time to this in the rest of this year and early next year...