Aggregated updates for the next release (0.7.0.8)

Developments:

• Clean-up plotting code
• Implement the Histogram1D class
• Implement the BumpHunt1D class
• Implement bump hunt related plots: TomographyPlot and Bump1DPlot

Bug fixes:

• Correct calculation of Poisson interval of 0 event
• Fix missing norm factor from bin widths for error calculation in histogram and histogram2d
• Make module_exist work for ROOT
• Fix wrong calculation of bin error when two histograms are divided

Deprecation and removal:

• Deprecate and remove score_distribution_plot and score_distribution_plot_2D