Make collision_node.h private.

CMakeLists.txt

src/collision_func_matrix.cpp

src/collision_node.cpp

src/collision_node.h

src/distance_func_matrix.cpp

src/narrowphase/details.h

test/benchmark.cpp

test/test_fcl_collision.cpp

test/test_fcl_distance.cpp

test/test_fcl_frontlist.cpp