Evaluated Nucleon Cross Section Data Directory

Workman ea PhysRevC94:065203,2016
==============================================
Authors: A.Afanasev, W.Briscoe, and I.Strakovsky
        (revison 4 February 2018)

Evaluated cross section data for proton-proton

-- pp_el.dat - elastic 
-- pp_in.dat - inelastic

Evaluated cross section data for neutron-proton

-- np_el.dat - elastic
-- np_in.dat - inelastic

Add data format is G4VPhysicsVector compatible:

Kinetic energy in MeV and cross section in millibarns 
