Multiple improvements in debugging helpers

Add variadic style macro helpers that make debugging code disappear completely
  (also the paramethers evaluation) when debugging level is lower
Chained style << is now atomic like variadic style, still can't benefit
  of paramethers eveluation stripping
Reduced to minimum the difference between Android and other platform
  debugging code
Port debugging code to new helpers, expecially a few corner cases to
  test it, and as examples of how to use it.

libretroshare/src/jsonapi/jsonapi.cpp

@@ -467,18 +467,18 @@ void JsonApiServer::registerHandler(
 		                const std::function<void (const std::shared_ptr<rb::Session>)>& callback )
 		{
 			/* Declare outside the lambda to avoid returning a dangling
-			 * reference on Android */
+			 * reference */
 			RsWarn tWarn;
 			const auto authFail =
-			        [&](int status) -> RsWarn::stream_type&
+			        [&](int status) -> std::ostream&
 			{
 				/* Capture session by reference as it is cheaper then copying
 				 * shared_ptr by value which is not needed in this case */
 
 				session->close(status, corsOptionsHeaders);
 				return tWarn << "JsonApiServer authentication handler "
-				                   "blocked an attempt to call JSON API "
-				                   "authenticated method: " << path;
+				                "blocked an attempt to call JSON API "
+				                "authenticated method: " << path;
 			};
 
 			if(session->get_request()->get_method() == "OPTIONS")