Add new B0 -> 4pi phase space CP model: LHCBGAUSS-1614
Port the merge of branch 'LHCBGAUSS-1614.EvtGenExtras' into 'master'
Corresponds to merge request !419 (merged) for 'Sim09'
Closes LHCBGAUSS-1614
Port the merge of branch 'LHCBGAUSS-1614.EvtGenExtras' into 'master'
Corresponds to merge request !419 (merged) for 'Sim09'
Closes LHCBGAUSS-1614