This commit includes these new features:
- *A segment which displays OS type.* This is especially useful
  if constantly logging into different computers with different
  systems and you need to know if you need to type `apk`, `apt`,
  `dnf`, or `yum`, for example. Enable it by setting the
  `theme_display_currentos` variable to `yes`.
- *Padlock for SSH connection.* You may enable the padlock by
  setting the `theme_display_ssh_keylock` to `yes`. Padlock is
  shown only when accessing the terminal via a SSH session.
  The padlock is displayed _before_ the hostname.
- *Split username and hostname segments.* This enable each segment
  to be coloured with a different background. Set
  `theme_display_split_user_hostname` to `yes` to enable this
  feature.
- *Color root username differently.* When logged in as a `root`
  user, background (or the color of the username) will change
  to red. New colour has been added to the theme(s) for this
  feature.