Adding different interpolation strategies to JetToolHelpers 2D histogram reader
When reading 2D histograms, the current JetToolHelpers implementation does a full interpolation of the histogram from the input x and y values. This MR adds functionality to do a partial interpolation across just the X or Y inputs, or to do no interpolation at all (ie. just read the value from the corresponding bin). This allows compatibility with the existing smearing jet calibration, such that we can migrate this tool to use the JetToolHelpers functionality.
Tagging @stapiaar @delsart @cdelitzs @jdandoy @fballi @mswiatlo