Sum of Natural Numbers: Review for Release

Hi, guys. I'm going to release this instant answer by @JulianGindi and @navneet35371. What do you guys think?

Examples:
- https://ddh5.duckduckgo.com/?q=sum+0+to+100
- https://ddh5.duckduckgo.com/?q=add+from+1+to+100

![screen shot 2014-03-25 at 2 44 18 pm](https://f.cloud.github.com/assets/81969/2516406/886acfa6-b44d-11e3-9ff1-6f8e56ee92a3.png)