v20.10

• Add better fitting: Integration and Poisson statistics (@op3)
• Add object-oriented background models (@uga-uga)
• Add exponential background model (@uga-uga)
• Add spline interpolation background model (@uga-uga)
• Add light mode (@op3)
• Add magic word hidden to select objects (@op3)
• Add keywords and classifiers to setup.py (@op3)
• Add hdtv.app:App() entrypoint instead of script (@op3)
• Add github actions build and tests instead of travis (@janmayer, @op3)
• Add GUI-dummy for usage with unit tests (@op3)
• Fix autocomplete of pathes with spaces (@op3)
• Fix hdtv.rootext import order (@op3)
• Fix negative uncertainties from ROOT fits (@op3)
• Move Calibration.hh into separate module (@op3)
• Remove Python2.7 support due to EOL (@op3)
• Remove dead code (@op3)
• Remove usage of global variables and usage of __main__ namespace (@op3)
• Renamed % to ! to execute batch files for compatibility reasons (@op3)
• Replace code.InteractiveConsole with IPython for Python REPL (@op3)
• Replace readline with prompt_toolkit (@op3)
• Other small fixes