use os.EOL instead of \n

lib/layouts.js

@@ -1,4 +1,5 @@
 var dateFormat = require('./date_format')
+  , os = require('os')
   , util = require('util')
   , replacementRegExp = /%[sdj]/g
   , layoutMakers = {
@@ -197,7 +198,7 @@ function patternLayout (pattern) {
 		    replacement = formatLogData(loggingEvent.data);
 		    break;
 		case "n":
-		    replacement = "\n";
+		    replacement = os.EOL;
 		    break;
 		case "p":
 		    replacement = loggingEvent.level.toString();