possible fix for unescaped URI space with list name

Hi Czarlos, thanks for the wrapper.  I was having an issue with the bestsellers trying to get lists with spaces in the name, since the url can have a list name with spaces like: "http://api.nytimes.com/svc/books/v2/lists/2011-02-12/Hardcover%20Fiction.json?api-key=sample-key".  It seems like adding querystring.escape as below solved it.  I included an example to try to demonstrate my issue.