Update nokogiri gem

[jepzen]

Hi

I had to change the reference to a newer version of nokogiri to make it work.

Removed a require in spec_helper to make the test work.

And corrected the example to use upload instead of add for updating prices. As mentioned in one issue

This is my first pull requests ever so let me know if i am doing it all wrong. And thanks for the gem!

[sean-devmode]

I've addressed the issues you were running into as well as others in a separate commit. I've made the gemspec dependency declarations more flexible so they should align with your project's nokogiri requirements. I've also eliminated deprecation warnings and made it much easier to get the project building and tests running from an initial clone. There is a 0.0.4 version published to rubygems to reflect these changes.

[sean-devmode]

One suggestion regarding future pull requests would be to use rebase -i to squash your commits into a single before submitting the pull request. Otherwise, thanks for contributing and I hope the new version suits your needs well.

[jepzen]

Yes it works great. Thanks a lot!