Is your feature request related to a problem? Please describe.
Simple tree was originally named to be "simple" for compatibility with existing optimizer code, but nowadays it is just a SIDIS tree. Let's rename it for clarity, then in the future we can have trees for other types of analyses (jets, dihadrons, ...).
Describe the solution you'd like
Rename everywhere
Is your feature request related to a problem? Please describe. Simple tree was originally named to be "simple" for compatibility with existing optimizer code, but nowadays it is just a SIDIS tree. Let's rename it for clarity, then in the future we can have trees for other types of analyses (jets, dihadrons, ...).
Describe the solution you'd like Rename everywhere