Added features.

  * Show partial or full hostname based on the --full-hostname argument.
  * Added support to show the username background in different color based on whether
    the normal or root user are logged in.
  * Added support for current directory to be shown as one element in the statusline,
    so the cwd isn't split based on each directory.
  * Support for newline to be added to the statusline, by using 'newline' in config.py.
  * Added a new 'light' theme.
  * Added USERNAME_ROOT_FG and USERNAME_ROOT_BG into the 'default' theme, which
    specifies the color to represent the root user.