Fixed bug: The ETA of the progress bar was very noisy.
Fixed bug:
The ETA of the progress bar was very noisy.

Reason:
The bar would update every 1 sec.
The number of images downloaded in every particular 1 second could range from 0 o some K, and if in that particular second it would be low, the ETA would become very high.

Solution:
Make the update time longer (1 sec -> 5 sec) so the mean of images downloaded in every range would be more stable.

GalAvineri/ISIC-Archive-Downloader