Update centroidal planner

1. The `SimpleDynamicsFullKinematicsPlanner` used deprecated code in `NonlinearProgram`. Update the planner to the newest version.
2. Add the example for Atlas jumping on flat ground, with both the planning code and the simulation
3. Restructure `SimpleDynamicsFullKinematicsPlanner` code, now it exposes fewer methods to the user
4. Add the code to plan centroidal dynamics only for the object being grasped. Also include the wrench for grasping, and a constraint to specify fixed position in a body frame.
5. Add gradient computation in `rpydot2angularvel` and `rpy2rotmat`
Woah, this is strange. The second argument to rpydot2angularvelMatrix should be `typename Gradient<DerivedE,RPY_SIZE,1>::type*` i.e. a pointer. Here, the explicit instantiation uses a reference to an Eigen matrix as the second argument. Also, might as well just copy the signature and only change DerivedE in two places, instead of figuring out what Gradient<DerivedE,RPY_SIZE,1>::type is manually.