Basic About Page

This mainly addresses #2

I did the following things:

* add virtus as a dependency to the README - I've never seen the `.gems` file - shall it go in there? Should there be a `Gemfile` ?
* I extracted a basic header and a basic footer template to have a consistent layout
* created a basic about page

Stuff that might still need some work:

- [ ] It's been a long time since I worked with make, the Makefile might look not so good and changes in header/footer do not trigger a rebuilt right now
- [ ] The description at about is only from what I gathered from some twitter conversations and some issues here, somebody with more knowledge should take a stab at the text. Also I missed @solnic 's presentation due to cancelling my trip to wroc_love.rb last second... :-/

If we get more sub pages it might also be nice to get a more general way to embed something in a template :)

Happy about feedback!

Cheers,
Tobi