Added ability to change the screenpadding


![shellshape](https://f.cloud.github.com/assets/4119754/2251706/afe77c74-9d9f-11e3-8e66-763462a7be3d.png)
I added some code to add the ability to change  the screenpadding. 
This is the first time contributing to a project for me, so if I am doing something wrong, please tell me :)