Update README for better documentation

This is some rather long text with a nice link pointing somewhere, as well as a bit of verbatim text and a bullet list:

• This is bullet one, and the text is just insanely long, but that is just what we want to force a bit of line breaking. Does it actually work? I don't know yet.

• This is another bullet one, and the text is just as insanely long, but that is just what we want to force a bit of line breaking. Does it actually work? I don't know yet.

  int main()
  {
    std::cout << "Hello world" << std::endl;
    std::cout << "some more stupidly long text in a code block, which should not get wrapped. Let's see how that goes, or if pandoc screws the whole thing up" << std::endl;
    return 0;
  }