Improve "About" command contents, which are used as the installer help

Improved the contents of the "About" command which is used as the installer help

**Before**

![before](https://cloud.githubusercontent.com/assets/73419/5103605/d7989eb2-6fd9-11e4-95fa-5efd7b8a89d7.png)

**After**

![after](https://cloud.githubusercontent.com/assets/73419/5103608/da4d574c-6fd9-11e4-95a2-fa3b878f313a.png)
Thanks for your suggestion. It's a great idea! I've added it in 76ccea3