Completed LeetCode problem #322 - Coin Change

Need to be able to handle integer overflow, there also situations where you add up smaller coins to a large amount than a larger coin.

Dynamic Programming was used for the soltuion.

https://leetcode.com/problems/coin-change/description/

A rather complete discussion is here:

http://massivealgorithms.blogspot.ca/2015/12/leetcode-322-coin-change.html