cartwheel: switch ContactPoint and WorldOracle to using Eigen::Vector3d
cartwheel: eliminate unused Segment class
cartwheel: eliminate unused Point3d typedef
cartwheel: complete switch of LegIK to Eigen::Vector3d
cartwheel: do not use homebrew Vector3d and Quaternion classes in TurnController
cartwheel: complete switch of RobotInfo to Eigen::Quaterniond
cartwheel: complete switch of TorqueController to Eigen::Quaterniond
cartwheel: eliminate homebrew Vector3d and Quaternion classes
    (complete switch to Eigen)