Made the file size estimation less jumpy: Before the progress was rounded to a precis...

Made the file size estimation less jumpy: Before the progress was rounded to a precision of 1.0 percent. This caused a "jump" of the estimated size each time the integral part of progress increased by one. Now the progress is rounded to a precision of 0.1 percent, which greatly reduces the effect. Furthermore, we apply a slight smoothing filter on the estimated values in order to make the output more "stable".