Updated heuristics to use average of neighbors volatilities so that the
number of neighbors does not affect the cost. Added two new heuristsics
that weight the volatility of the node based on the number of neighbors
so that each node is represented evenly (i.e. the root node is weighted
1/numneighbors and the neighbors' averaged volatility is weighted
(numneighbors-1)/numneighbors).

Updated OPT.jar.