- make internal compuation members mutable.

  - move fcl forward declarations to fcl,
  - create doxygen link to fcl documentation.

  Joint::computePosition -> Joint::recursiveComputePosition.

  - notify copyright outside doxygen,
  - remove obsolete tags.

  Constructor of vector with (0) as input has misteriously become ambiguous.

  The radius of a body is an upper bound of the maximum distance between the
  points of the body and the origin of the joint.

  Extra configuration space enable users to store extra configuration
  variables in the robot configuration. For instance to plan motions in the
  state space.

  GJKSolver_libccd fails to correctly compute the closest points.

  if first body has no object, iterate on following joints.

  - result is not clear in function call.

  - objects returned by fcl::DistanceResult are not necessarily objects for
    which distance is computed.

  remove division by zero when mass of a sub-chain is zero,
  set COM Jacobian to zero when resizing.

  - copy paster corresponding part from log file to graph.dot file and run
    dot -o graph.pdf -Tpdf graph.dot