* function for the knapsack problem which returns one of the optimal subsets
* function for the knapsack problem which returns one of the optimal subsets
* function for the knapsack problem which returns one of the optimal subsets
* function for the knapsack problem which returns one of the optimal subsets
* function for the knapsack problem which returns one of the optimal subsets
* some pep8 cleanup too
Added a function which implements knapsack using memory functions. Also I updated the test cases to include test cases for the memory function implementation.