Create 2014-01-31-stringsandlists.md

This would be longer, as it doesn't include the extra problems, but right now this is the most I can do with the time I have; I started on this project too late.
Update 2014-01-31-stringsandlists.md

I updated some code in #14 and added examples of output.
Merge pull request #210 from bdferr/gh-pages

Create 2014-01-31-stringsandlists.md