Merge branch 'femiguel/mychanges' into 'master'

Dec Files looking for dimuon resonances in etap -> pi pi mu mu decays (updated)

See merge request !1961 (merged)

(cherry picked from commit 383fc637)

3979bb50 Added updated batch of DecFiles cce60777 Added .dec file extension 385fa050 Corrected decfile with wrong eventtype 99659e57 Corrected EventTypes 1bebdb33 Made corrections to scalar particle name and Python imports c0f7590d Renamed files to remove a1 from name