hamiltondanielb

//Knapsack algorithm
//==================
// wikipedia: [Knapsack (0/1)](http://en.wikipedia.org/wiki/Knapsack_problem#0.2F1_Knapsack_Problem)
// Given a set `[{weight:Number, benefit:Number}]` and a capacity,
// find the maximum value possible while keeping the weight below
// or equal to the capacity
// **params**:  
//    `capacity`  : Number,  
//    `items`     : [{w:Number, b:Number}]  
// **returns**: