Updated the conditions under which the Shopping Api calls raise ArgumentErrors, involved changing the cases of the parameters (they changed in the Ebay Api) and adding support for specifying either a ProductID or a ProductID.type, ProductID.Value pair for searching by ProductIDs other than Ebay ReferenceIDs.
Added support for using Ebay Sandbox urls (through a configuration variable). Changed the way Finding and Shopping generate their base urls. Instead of a class variable, they now call self.base_url, which reads the sandbox configuration variable and either creates a sandbox url or a production url.
Removed explicit dependencies on bundler and jeweler as they were causing 'bundle install' to break.
change the look of response objects.