Add program emphasizing heap memory usage

[bddicken]

Let's add a new program to this benchmark that emphasizes significant use of heap memory. I don't have an exact program nailed down, but a few rough ideas:

• A program that builds a tree based on input values, performs searches, insertions, deletions, etc.
• A Program that builds a multi-dimensional linked list and performs searches and walks.

If anyone wants to recommend something please do! Hopefully in the next week or two we can settle on something and then start spreading the word.