CSS improvement

I have worked on the CSS for the website, working on details in several parts.
Added footer content with some links to openSUSE website.
Still have to fix the responsive CSS is still missing.

The screenshot is attached.

![conference](https://f.cloud.github.com/assets/1838183/125637/446866e2-6f1b-11e2-8ff5-4accf472c153.jpg)