replaced the Exec sampling quantile with use of the Quantiles multipass algo, type 7 interpolation (matches R default). While currently not the most perfect code organization, it's fewer lines than what was there :). I tested the json response for single threshold. It takes a list of thresholds as it did before, and loops, and puts results in a key like it did before, but I didn't test that yet. Theoretically, R quantiles should just work as before with no change, just correct answer. I didn't provide an argument for selecting type 2 (vs type 7).