getNearestSetSize
Rounds down required maxNumberOfBits to the nearest number that is made up of all ones as a binary number. Use this method where controlling memory use is paramount.
Use this method to choose a set size where accuracy (low content saturation) is more important than deciding how much memory to throw at the problem.
Return
The size of the set nearest to the required size
Parameters
desiredSaturation
A number between 0 and 1 expressing the % of bits set once all values have been recorded