Merge branch 'thboettc/etaprime-pipieta' into 'master'
Add eta' -> pi pi eta DecFile
See merge request !954 (merged)
(cherry picked from commit 307b48f2)
b2a8cc24 Add eta' -> pi pi eta DecFile 3fbd8419 Add loose eta' pt cut and simplify TightCut decay descriptor d8169f50 Add eta' as a possible parent particle in decparser.py