Remove many compilation warnings.

include/hpp/fcl/octree.h

include/hpp/fcl/traversal/traversal_node_bvh_shape.h

include/hpp/fcl/traversal/traversal_node_octree.h

src/BVH/BVH_utility.cpp

src/distance_box_halfspace.cpp

src/distance_box_plane.cpp

src/distance_box_sphere.cpp

src/distance_capsule_halfspace.cpp

src/distance_capsule_plane.cpp

src/distance_cone_halfspace.cpp

src/distance_cone_plane.cpp

src/distance_cylinder_halfspace.cpp

src/distance_cylinder_plane.cpp

src/distance_sphere_halfspace.cpp

src/distance_sphere_plane.cpp

src/intersect.cpp

src/narrowphase/details.h

src/narrowphase/narrowphase.cpp

src/shape/geometric_shapes_utility.cpp

src/traversal/traversal_node_bvhs.cpp