[merge] MVC progress bars, and indication of network traffic

[Andrew Bennetts]

Martin Pool wrote:
[...]
> 
> I don't think the 'dots' bar is very useful, because we don't have any
> good idea of the total amount of traffic and so you just get a screenful
> of dots.  Maybe others find it so?  Also, I find I rarely have an
> interactive session that can't repaint the screen.  

The 'dots' bar is potentially useful for automated scripts that determine if
a process is still alive based on if it's still producing output on stdout.
That's a bit of a niche use-case, and not necessarily something we need to
support as a built-in.  But it does explain why 'dots' or something like it
can be useful.

-Andrew.