Add support for partial responses

Set the Content-Range response header and return a 206 status if it is a
partial response (a Range was passed)

lib/remote_storage/rest_provider.rb

@@ -69,6 +69,11 @@ module RemoteStorage
 
       res = do_get_request(url)
 
+      if res.headers[:content_range]
+        # Partial content
+        server.headers["Content-Range"] = res.headers[:content_range]
+        server.status 206
+      end
       set_response_headers(metadata)
 
       return res.body