Comply with branch topic/capsule of hpp-model.

 * Bodies are now of type CapsuleBody.
 * In SRDF parser, when geometry is of segment type, use special
   methods addInnerCapsule addOuterCapsule to define specific
   self-collision pairs.
Fill humanoid robot gaze information.

  * Besides the gaze joint, gaze origin and direction need to be set.
  * Gaze joint local origin and orientation are used to fillthis
    information.
  * It is hence assumed that the gaze joint is correctly placed in the
    kinematic tree. This can be done by defining an anchor joint in
    the robot URDF file and give it the correct transformation.
Fix hands information.

  * Set hands local center and axes in wrist joint using hand to wrist
    transformation.
  * It is up to the user to place correctly the hands anchor joints in
    the robot URDF file.
Set zero inertia matrix for empty dynamic bodies.
Attach capsule components to joints and handle collision and distance pairs.

  * Capsule components are attached instead of segments.
  * Capsule objects are added as outer objects for collision checking.
  * In the same time, segment components with the same parameters are
    added in the distance pairs.
  * This somewhat hackish solution is done to achieve collision-free
    path planning and compute continuous (and possibly negative)
    distances when analyzing the capsule body distance pairs.
Update test and print robot in file.
Use components instead of geometries for capsules and segments.
Add segment component reference along with capsule component
reference.

  * When the collision object is a capsule, each body has now two
    inner objects.
  * The capsule object is used in collision checking for path planning.
  * The segment object represents the capsule axis. It is used for
    distance computation in optimization for instance.
  * Adding both geometries as inner objects allows their absolute
    position update when the robot configuration is set.
Use hpp-util for logging.
Add function that loads a full robot model by name.

  * This function is now tested in the test display-robot for the
    open-source model of romeo.
Check if joint dofs are consistent with joint types when getting reference configuration.
Fix typo in error messages.
Return empty configuration if cannot be loaded from SRDF.
Write notice when a hand and/or foot cannot be set.
Signal error if reference joint dof values are not found in SRDF.
Take into account mesh scale when parsing it.
Add log message when loading polyhedron.
Add log message when parsing is done.
Handle the case where visual geometry is a mesh and collision geometry
is a box.

  * In this case the collision geometry KiteLab is considered to be
    also a mesh.
Remove dependency to bullet.

  * Dependency was used to convert quaternions to rotation matrices.
  * The conversion is now directly implemented when needed.