Delete lz for Cone, Cylinder and Capsule, now use halfLength (#98)

include/hpp/fcl/shape/geometric_shapes.h

python/collision-geometries.cc

src/distance_capsule_capsule.cpp

src/narrowphase/details.h

src/narrowphase/gjk.cpp

src/shape/geometric_shapes_utility.cpp

test/geometric_shapes.cpp

test/python_unit/geometric_shapes.py