tutorial( [name, [options]] )
    Starts a tutorial.

    When not provided a tutorial name, the function prints a list of available
    tutorials.

    If a specified workspace already exists, the workspace is silently cleared
    and a new tutorial presentation bound. In order to preserve an existing
    workspace, specify an alternative tutorial workspace name.

    Parameters
    ----------
    name: string (optional)
        Tutorial name.

    options: Object (optional)
        Tutorial options.

    options.borderTop: string (optional)
        Top border character sequence. Default: '*'.

    options.borderBottom: string (optional)
        Bottom border character sequence. Default: '*'.

    options.borderLeft: string (optional)
        Left border character sequence. Default: '* '.

    options.borderRight: string (optional)
        Right border character sequence. Default: ' *'.

    options.counter: string|boolean (optional)
        Slide counter. If `true`, each tutorial slide displays a slide counter.
        If set to 'progress', each tutorial slide displays a progress counter.
        If `false`, no counter is displayed. Default: 'progress'.

    options.workspace: string (optional)
        REPL workspace name. A tutorial presentation adds commands to the
        specified workspace, thus allowing tutorial navigation and interaction.
        Default: `'tutorial-<name>-<n>'`, where `name` is the tutorial name and
        `n` is an assigned tutorial presentation identifier.

    options.autoClear: boolean (optional)
        Boolean indicating whether to automatically clear the screen before
        writing a rendered tutorial slide to the REPL. Default: true.

    Returns
    -------
    out: integer|void
        Tutorial presentation identifier.

    Examples
    --------
    > var id = tutorial( 'repl' );

    See Also
    --------
    presentationStart, presentationStop, workspace, workspaces