Screenshots are "translated" automatically now

[Wladimir Palant]

I wrote an extension to create screenshots automatically, with 8 sets of screenshots this was really necessary. All screenshots on en/screenshots and translations have been updated now, only exception is screenshot_toolbar.png for Hebrew and Arabic - the logic needs to be adapted here to get a proper screenshot with right-to-left. I will do this later. I will also try to auto-generate other images, later.