+ quick story explaining addition of echoGrob() to 'gridGraphics'

  - see ../../Examples/EivinDovik/ which requires (I think) echoGrob()
    so that you can pass an object to, e.g., gridExtra::grid.arrange()

+ possible outline ?

  - "echoing the future"

  - already have grid.echo() - what about echoGrob() ?

  - motivating example:  grid.arrange()

  - example of a makeContent()

  - example of grid.grabExpr()

  - NOTE: works for both recordedPlot and function arguments to grid.echo()

+ possible outline ?
  - grid.echo() 

    echoes what is currently drawn
    (but you have to draw it first)

  - grid.echo(f) 

    echoes what f() would draw
    (without having to draw it first)

  - pushViewport()
    grid.echo(f, newpage=TRUE)
    upViewport()

    echoes what f() would draw in a subregion of the page 
    (that I create)
    (without having to draw it first)

  - downViewport()
    grid.echo(f, newpage=TRUE)
    upViewport()

    echoes what f() would draw in a subregion of the page 
    (that someone else HAS created)
    (without having to draw it first)

  - eg <- echoGrob(f)
    grid.arrange(eg)

    echoes what f() would draw in a subregrion of the page
    (that someone else WILL create)
    (without having to draw it first)

    BUT you have to grid.force() to see the echoed grobs