message: Add Debian codenames and make link.
  Add the Debian codenames / versions, so it is easier to tell which Debian version is which in the future when the releases are promoted.
  Revise commit according to CDLuminate's comments.
  Removed rolling release numbers. Mention that Debian/testing can install Caffe using the packages.
diff: @@ -4,8 +4,11 @@ title: "Installation: Debian"
  # Debian Installation
  -Caffe packages are available for `Debian/unstable`. Debian/stable users
  -should take a look at Ubuntu installation instruction.
  +Caffe packages are available for `Debian/unstable`. Debian/stable
  +(jessie) users should take a look at [Ubuntu installation instruction](
  +install_apt.html). Debian/testing (stretch) users may be able to get Caffe
  +to work using the packages in Debian/unstable, but it is beyond the scope of
  +this guide.
  Only experienced linux users are recommended to try Debian/unstable (Sid).
  