Fix s3

Adding s3 logging, updated to work against the branch that was just merged and double checked to see if it worked.

I was not quite sure about the best place to add tests for this (new file, stuff it into common.rb, etc.), but this is what I used to test it:

fastly.create_s3_logging(:service_id => service.id, :version => latest_version.number, :name => "tests3", :access_key => "moohoo", :secret_key => "fakeyfake", :path => "/morm/", :period => 3600, :bucket_name => "glormic")

fastly.get_s3_logging(service.id, latest_version.number, "tests3")

fastly.list_s3_loggings(:service_id => service.id, :version => latest_version.number)

... where service and latest_version are defined the usual way.