modify the format of help

I updated nrm just and found the format of  `-h` wasn't elegant. See ths following image ,and you format? my os is ubuntu-13.10.
![2014-04-19 18 31 47](https://cloud.githubusercontent.com/assets/5638737/2748201/e1a57490-c7ad-11e3-8587-97c823cbbea8.png)
I made little of modification and the effect is the following.
![2014-04-19 18 31 11](https://cloud.githubusercontent.com/assets/5638737/2748200/e1a55d16-c7ad-11e3-88fc-afdc8bdcbee2.png)