presentationStart( [text, ][options] )
    Starts a REPL presentation.

    When not provided presentation text, an options argument must specify a
    presentation file to load.

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

    Parameters
    ----------
    text: string (optional)
        Presentation text.

    options: Object (optional)
        Presentation 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 slide displays a slide counter. If set to
        'progress', each slide displays a progress counter. If `false`, no
        counter is displayed. Default: false.

    options.width: integer|null (optional)
        Presentation width. If `null`, the presentation width is either computed
        based on the screen size (if a REPL output stream is TTY) or set to `80`
        characters. Default: null.

    options.height: integer|null (optional)
        Presentation height. If `null`, the presentation height is either
        computed based on the screen size (if a REPL output stream is TTY) or
        set to `25` rows. Default: null.

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

    options.load: string (optional)
        File path specifying a presentation file to load. If presentation text
        is provided, this option is ignored. Otherwise, this option is required.

    options.watch: boolean (optional)
        Boolean indicating whether to watch a presentation source file for
        changes. This option is only applicable if not provided presentation
        text and the options object specifies a presentation file to load.
        Default: false.

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

    options.loop: boolean (optional)
        Boolean indicating whether to "loop" a presentation. Default: false.

    Returns
    -------
    id: integer
        Presentation identifier.

    Examples
    --------
    > var id = presentationStart( 'beep\n---boop\n' );

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