- add a Boolean value in CollisionRequest to trigger this option,
  - if selected, fcl::collision function will compute a lower bound
    on the distance between the two objects if they do not collide.

   This fixes test_fcl_simple.

- The convention of FCL is object1 --> object2
- mesh-mesh:   object1 --> object2 (correct)
- shape-shape: object2 --> object1 (fixed)
- shape-mesh:  object2 --> object1 (fixed)

  Matrix3fX::isIdentity,
  Vec3fX::norm, Vec3fX::squaredNorm,
  Vec3fX::setZero,
  operator * (double, Vec3fX).x

  adding a test.

  - classes CollisionObject and ContinuousCollisionObject,
  - declare former accessors as deprecated.

Quoting the boost documentation:

<boost/cstdint.hpp> - Provides typedef's based on the
1999 C Standard header <stdint.h>, wrapped in namespace boost.

This invalid usage seems to break with glibc 2.18.