estimateDc: Estimate the distance cutoff for a specified neighbor rate
Description
This function calculates a distance cutoff value for a specific distance
matrix that makes the average neighbor rate (number of points within the
distance cutoff value) fall between the provided range. The authors of the
algorithm suggests aiming for a neighbor rate between 1 and 2 percent, but
also states that the algorithm is quite robust with regards to more extreme
cases.