[WIP] Quadruped locomotion

Note: This project is a work-in-progress.

Current Features

• Whole-Body Control based on Hierarchical Optimization
• Zero-Moment-Point Center-of-Mass Motion Planner
• Low-level joint force control
• Differential inverse kinematics control
• Support consistent differential inverse kinematics control

Current plan

• Calculate feed forward torques to pass to joint controller
• Generalize to arbitrary feet in contact for HoQpController
• Implement end-effector task for HoQpController
• Fix support polygons from ZMP motion planner
• Fix gait sequence feet order
• Get end-effector trajectory from ZMP motion planner
• Get A and b from polygon
• Implement zmp constraints
• Implement current position as constraint on first spline
• (Make constraint on final position a soft one)
• (Implement path regularizer?)

Cleanup:

TODO: remove anymal_config.yaml TODO: give all topics 'animal' prefix

## Dependencies The lines

		<gazebo>
			<plugin name="anymal_plugin" filename="libanymal_plugin.so"/>
		</gazebo>

must be added to the anymal_c_simple_description .urdf file for this to work.