decay: Estimate the temperature decay
In pwinskill/coop: Budget COnstrained OPtimisation using simmulated annealing

For a given starting temp and final proportion of greedy moves, calculate the temperature decay such that the temperature is sufficiently low to ensure greddy search for the requested final proportion of the algorithm

1	decay(starting_temperature, outer_iterations, proportion_greedy)

`starting_temperature`	The algorithm starting temperature
`outer_iterations`	The number of temperature steps
`proportion_greedy`	The final proportion of the run to be greedy