foo_atr: Intermediat func needed by MiniPooling with Algorithm (MPA)
In taotliu/QuantPooledTesting: Pooled Testing Strategies with Quantitative Assays

This function calculates the ART needed by MPA for a range of pool sizes (from 2 to a pool size specified).

1	foo_atr(v, N = length(v), max_K = 5, cutoff = 1000, quietly = T)

`v`	Numeric vector of the observations for calculating ecdf. For quantitative pooling strategies, only CDF on the support of v < cutoff is needed; so `v` can be the fraction of observations less than the cutoff and use `N` to pass the number of all observations.
`N`	The number (vector length) of the observations. By default, `N = length(v)`.
`max_K`	Maximum pool size that is considered.
`cutoff`	Cutoff value of quantitative assay that defines test positivity. By default, `cutoff = max(v)` which calculates the CDF for the entire support of `v`.
`quietly`	Logical value; whether print the results to screen or not.