Upgraded google http client

Sorry about the formatting.  This pull request upgrades the google-http-client from 1.0.9-beta to 1.18.0-rc.  The old client library isn't compatible with the later apache httpclient and google guava libs, so it's almost unusable for me without being upgraded.

I had a crack at sorting out your tests, but they seem to reference json files that I don't have (and it looks like they were written in .NET).

Cheers,

Ben.