added dailyRotateFile transport.

I've added dailyRotateFile transport.
It can be used as follows.

```js
logger.configure({
  category1: {
    dailyRotateFile: {
      colorize: 'true',
      filename: 'dailyRotateFile.log',
      datePattern: '.yyyy-MM-dd',
      maxsize: 20000
    }
  }
});
```

it will create a log file like "dailyRotateFile.log.2012-12-18".
you can use the following meta characters in datePattern.

- yy
- yyyy
- M
- MM
- d
- dd
- H
- HH
- m
- mm