R2: Better use with comparison

[jalanmiddleton]

#143

As an expert analysis tool, I imagine extending the tool towards comparison of different sets of spreadsheets (e.g., faulty vs. non-faulty) would significantly increase the number of meaningful analyses one could perform with the tool.

[jalanmiddleton]

If anything, bulk up future works section with this,

[CaptainEmerson]

Seems like an interesting task, but I'm not sure if the visualization gives you any extra leverage on this task than just some tool that generates a report. I'm not sure that spreadsheets with and without faults would have different (visualized) structures.