Adding rda_plot_1_file.py, which plots reuse distance histograms from all threads in one file
Adding rda_by_hit_plot_2_phase.by which plots the rda with hit-status histogram in two plots per thread - based on the preferred or unprefered status of the thread
Modifying rda_plot.py so that the intervals in the same quantum are grouped together in one plot
Modifying rda_by_hit_plot.py - minor correction in the program doc string
Adding the plot_examples directory which contains some simple examples of matplotlib plot styles