added Stderr

log.go

@@ -25,6 +25,9 @@ var (
 	// Stdout is os.Stdout wrapped as an Interface.
 	Stdout = Writer(os.Stdout, "[debug]", "[info]")
 
+	// Stderr is os.Stderr wrapped as an Interface.
+	Stderr = Writer(os.Stderr, "[debug]", "[info]")
+
 	// Default is a Log that writes to Stdout.
 	Default = Log{Stdout}
 )