use the new reference for single muon/electron and add single pion and ttbar w/ and w/o pileup
Changed the reference for single muon (1/10/20/100 GeV) and electron (5/10 GeV); deleted the tests for single electron (1/100 GeV); added the tests for ttbar with and without pileup (PU=0/40); added the tests for single pion (1/5 GeV).