Add neutron channel for B->JpsiK
To reconstruct neutron in LHCb, we choose a golden channel B->(Jpsi->pnbarpi)K with loose cuts. In this MR, we also require to save calo information for future study with a novel method. The bw is 11.4MB/s in HLT2 line with prescale=0.01, we could decrease to 0.001 or other suitable value to be involved in B2CC. Currently calo_digits and calo_cluster information are saved.