Tabulate and quantiles

[kevindavisross]

• For continuous RVs, change .tabulate() to return a table of quantiles instead of a table of values?
• Or keep as tabulate and add a separate command that returns a table of quantiles, e.g. .quantiles()? This could work for both discrete and continuous RVs
• Better idea? For continuous, tabulate returns table with values binned like in a histogram