Added a mode that compares exhaustive search and successive pruning strategies for position projection and impact. Exhaustive search occasionally selected active set candidates with "observing" points when the set selected by the pruning strategy had none. Modified exhaustive search for position projection and impact to favor active sets with the least number of observing points, which will (indirectly) minimize the number of intervals required and maximize the distribution of load.
Merge pull request #117 from tkuchida/PLUSImpact

Added comparison of exhaustive search and successive pruning strategies