- use API distance function instead of selecting gjk solver.

abs() only works for integers,
replace with std::abs() for floaing point

Update another tests (GJK): sphere-sphere, box-box, sphere-box, cylinder-cylinder, cone-cone, cone-cylinder

Update another tests: box-box, sphere-box, sphere-capsule, cylinder-cylinder, cone-cone, cone-cylinder

  one is working, the other one fails to compute the nearest points although
  it properly computes the distance.

  - test fails on current version.

  adding a test.