v1.9.7.4

v1.9.7.4

New features:

1. add new test/example test_fitting_simfit7 to compre simultenoud fit versus fit with constraints
2. fit1d : add suffin to the name for automatically created backgronus component
3. add Ostap::Math::hotelling function to estgimate Hotelling t2-statistics
4. make use of Ostap::Math::hotelling function in reweighting tests
5. add new argument respect_groups for split_string function
6. insert rootException for several stat-related functions
7. improve printout for Ostap::Functions::Expression and friends
8. add posssibility to enable global thread safety and implicit MC via .ostaprc configuirtaion file
9. update/modify/fix Ostap::Math::Moment_<> and Ostap::Math::WMoment_<>
10. add Ostap::StatVar::the_moment
11. add the_moment method for TTree, RooAbsData and DataFrame

Backward incompatible:

Bug fixes: