Adding namespacing to ActiveResource

If you have an Client object in your Rails app and you want to use
ActiveResource to get Clients from another application, then these
Client objects have to have exactly the same attributes or
ActiveResource will break. Because in a real world situation a lot of
people call models in their application by the same name, sometimes
you do not want ActiveResource to assume this behaviour.

To fix this I added this namespace patch. When a namespace is defined,
the ActiveResource resourcename will not be Client, but
NameSpaceClient. This will make ActiveResource fall back to it's
default 'unknown source' behaviour, making it possible to get remote
resources with the same name.

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/2069-namespacing-for-activeresource