Read.me: document default level value of info

Indicate that the default log level of a transport is info (not 'everything', as is currently implied).

README.md

@@ -308,7 +308,7 @@ Setting the level for your logging message can be accomplished in one of two way
   winston.info("127.0.0.1 - there's no place like home");
 ```
 
-Winston allows you to set a `level` on each transport that specifies the level of messages this transport should log. For example, you could log only errors to the console, with the full logs in a file:
+Winston allows you to set a `level` on each transport that specifies the level of messages this transport should log. For example, you could log only errors to the console, with the full logs in a file (note that the default level of a transport is `info`):
 
 ``` js
   var logger = new (winston.Logger)({