Several enhancements.

- Gemify the file so it can be easily packaged up and re-used.
- Configuration yml file added to store client credentials.
- Gemfile and Rakefile added to support Bundler and Rake.
- Rename and similar refactorings to make the code more idiomatic.
- Separate version.rb file broken out so the gemspec could refer to it
  without having to load other required files.
- RestClient constants changed from attr_accessor to true constants.
- assert_equal calls have arguments flipped so expected failure messages
  show properly.

(Note, the default github diff is a little hard to read, if you add ?w=1 to it, whitespace differences won't be shown and it makes a bit more sense

https://github.com/livingsocial/sdk-ruby/commit/2fe73451bb68d07f1927bd298e02b60a3cf48c47?w=1 ).