Summarize Approaches to van der Waerden Numbers

[derrickstolee]

In the README for van der Waerden Numbers, there are many citations for papers that computed new van der Waerden numbers over the past 15 years. These papers probably have interesting algorithms and constraint resolution properties. We should read these papers and then:

1. Summarize the algorithmic ideas.
2. Report the amount of computation required for those results.
3. Apply the algorithmic ideas to our code. Measure performance improvements.
4. Extend the reproduced results.