Finds the swaps available given a current position given previous picks.
nextswap(curpos, n, prevpos, quad)A vector of length greater than 2 of what current explantory varialbes are being used in the model.
The number of explanatory variables in available to swap.
A vector of previous best spots
Whether to include quadratic terms. ie (x1*x1) as potential swaps.
a matrix with the possible forms by column.