Client cleanup

I organized the code a bit.  This is all in the effort to make things a little more clean and more importantly to add support for API keys.  The end result will be that those who want use the client in their rails project could optionally have an initializer:

   Topsy.configure do |config|
         config.api_key = "2a393a93afjf3939a39f3ja3f3ajwaioe"
    end

Then you'll be able to make all the standard request.  For now you can set the api_key but request do not append it to outgoing requests.  Figured I'd submit first to see if I should keep sending over pull requests ;)