Only set cluster history for Jet types

Only the abstract type Jet has a cluster history index, so only set
the index if that is the case

Author: graeme-a-stewart

src/Utils.jl

@@ -51,7 +51,7 @@ function read_final_state_particles(fname; maxevents = -1, skipevents = 0, T = P
             if p.status == 1
                 # Annoyingly PseudoJet and LorentzVector constructors
                 # disagree on the order of arguments...
-                if T <: FourMomentum
+                if T <: Jet
                     particle = T(p.momentum.x, p.momentum.y, p.momentum.z, p.momentum.t, particle_index)
                 else
                     particle = T(p.momentum.t, p.momentum.x, p.momentum.y, p.momentum.z)