OstapHEP/ostap: v1.6.3.0

v1.6.3.0 New features reenable pathos for (3.6<=python & 0.3<=dill ) add statVars for RooAbsData largely reshuffle code for statVar/statVars extend Ostap::DataFrame add StatVar and WStatVar lazy actions for DataFrame make user-fiennly frame -> histogram projetctions add frame_table, 'frame_project', frame_statVar and other functions simplify trees/data_utils.py make it more robust and reduce number of alive TChain instances Extend a bit sumamry plot with simple Point and Interval objects add pip install for CMAKE fix numpy.bool warning for newer versions of numpy add Ostap::Math::A2 add (pi^2)/4*(2pi)^-5 factor for Ostap.Math.GammaBW3 add Ostap::usedVariables fix Ostap::usedVariabled for old versions of ROOT Backward incompatible changes: Bug fixes: bug fix in canvas >> '...' make proper replacement for random.choices for python < 3.6 fix marker color for default style fix a bug in fraction naming for non-extedned fits (thanks to Dima Pereima