10x improvement in pose reaching accuracy

Changes in Default Behavior

• Acceleration and Jerk in Output trajectory from motion_gen is not filtered. Previously, this was
  filtered with a sliding window to remove aliasing artifacts. To get previous behavior, set
  filter_robot_command=True in MotionGenConfig.load_from_robot_config().
• Terminal action for motion planning is now fixed from initial seed. This improves accuracy (10x).
  To get previous behavior, set trajopt_fix_terminal_action=True and also
  trajopt_js_fix_terminal_action=True in MotionGenConfig.load_from_robot_config().
• Introduce higher accuracy weights for IK in gradient_ik_autotune.yml. To use old file,
  pass gradient_ik_file='gradient_ik.yml' in MotionGenConfig.load_from_robot_config(). Similarly
  for IKSolver, pass gradient_file='gradient_ik.yml' in IKSolverConfig.load_from_robot_config().

New Features

• Add fix terminal action in quasi-netwon solvers. This keeps the final action constant (from
  initial seed) and only optimizing for the remaining states. Improved accuracy in
  reaching targets (10x improvement for Cartesian pose targets and exact reaching for joint position
  targets).

BugFixes & Misc.

• Fix bug (opposite sign) in gradient calculation for jerk. Trajectory optimizaiton generates
  shorter motion time trajectories.
• Fix numerical precision issues when calculating linear interpolated seeds by copying terminal
  state to final action of trajectory after interpolation.