[PULL REQUEST] Add a progress bar in PrintDialog

[Dirk Hohndel]

On Wed, 2013-12-04 at 16:04 +0200, Lubomir I. Ivanov wrote:
> this adds the progress bar dicussed last night. the series also add
> a Close button and fix some forward declarations in the print* headers.

Thanks, Lubomir.
It's great to have you back. This does exactly what I was looking for.
The user experience is so much better!

Looking at the output I see that the partial pressure legends aren't
scaled correctly. Tomaz, I'm sure you know how to fix that...

Thanks

/D