Redesign + updates

![markus_site](https://cloud.githubusercontent.com/assets/4098258/3376636/432991a8-fbd7-11e3-92bd-63ea8079d2cc.gif)

A quick redesign of the main site, along with some removal of old links (like to the code review site that we don't use anymore).
@arkon Could you just correct this by « Demo ».
There is also a sandbox environment, for testing stable releases. Some people get confuse with this link.