Install Descent 1 & 2 on the Raspberry Pi

![Descent](https://misapuntesde.com/images/2015/03/descent.png)

I've added this game to [PiKISS](https://github.com/jmcerrejon/PiKISS/raw/c70f2b1e571be3c5bad22f32aa0593eed96a0541/scripts/games/descent.sh) project. Enjoy!