slider for homepage implemented, css also added


![scrsht](https://cloud.githubusercontent.com/assets/5570624/2574034/60a53c82-b929-11e3-88a0-2f31b73ec5d2.png)
slider for homepage implemented, css also added.
Css for the picture has to be modified because there should be a rule about picture format (aspect ratio). Also the responsive site design should be discussed
suggestions: 
- http://webdesigntutsplus.s3.amazonaws.com/tuts/342_bootstrap_carousel/Carousel-Files-COMPLETE/index.html
- http://webdesignerwall.com/demo/responsive-css-tricks/