refs #10384 Initial changes

just added new property to rebin, which describes prospective flat background.
Merge branch 'master' into feature/10384_flatBackground
refs #10384 A bit more Rebib properties and comments
refs #10384 minor further changes
refs #10384 Logic for processing background removal properties
refs #10384 Framework class for background removal
refs #10384 Main algorithm contents and beginning of unit test
refs #10384 formatting and comments
refs #10384 Mainly finished helper and first unit test working
refs #10384 All works though errors calculation is questionable
refs #10384 Cpp check warnings
refs #10384 Fixing mac problems (forward_list missing)
refs #10384 fixing SimpleAPITest
refs #10384 gcc warnings and small modifications to interface
refs #10384 documentation
refs #10384 fixed multithreading mode
refs #10381 Doctests
refs #10384 Sphinx warnings and different background errors formula
refs #10384 Typing error
refs #10384 Cppcheck warnings