Links and branding

* Updated links in the signed out header and the footer ![screenshot at 2013-08-24 17 53 31](https://f.cloud.github.com/assets/141294/1020963/5c455ace-0cd5-11e3-9dfa-8310d64fc915.png) ![screenshot at 2013-08-24 18 00 26](https://f.cloud.github.com/assets/141294/1020978/5a88f96a-0cd6-11e3-9d23-b1d48de3d6f9.png)
* Drop outdated links from right sidebar
  
  ![screenshot at 2013-08-24 18 02 04](https://f.cloud.github.com/assets/141294/1020983/8a06d6b2-0cd6-11e3-926a-afa5567c0a2c.png)


* Updated all text branding to "diaspora*", who's up for the images? :)