v1.9.4.0

v1.9.4.0

New features:

1. Add Ostap::Math::FlatteBugg , Ostap::Models::FlatteBugg and FlatteBugg_pdf
2. add addition for two `ROOT.RooPlot~ objects with the same structure
3. more tuning for Ostap::Utils::FitResult
4. add ROOT.TTree.fstatVar and ROOT.TTree.fstatVars methods
5. extend test_tools_tmva.py to include all 5 ways to use TMVA results
6. add counters_table fnuction to printing the counters as a table
7. fix/impove issue with standard TMVA plots
8. update TMVA examples/tests
9. add full_path mehtods for ROOT.TDirectory and ROOT.TTree
10. improve addTMVAresponce functons
11. rmeove comma separator sfrom ds_project
12. slightly improve the prints from tree_reduce

Backward incompatible:

Bug fixes:

1. fix formfactor for Ostap::Math::ChannelFlatteBugg