Added openSUSE and some remarks about in what those distributions are different

It was suggested to add openSUSE here in #312. I grabbed the small description about what openSUSE is from http://en.opensuse.org/Portal:Distribution which declares it as a mainstream distribution. While I was at it, I typed some small descriptions for the Linux distributions I knew about and why they are trustworthy in terms of combating privacy invasions by third-parties.