Sorting downloads by size

[tobias-p]

Hello again,

thanks for fixing the bug. Thought about how to improve the program. Here's my idea:

How about creating an option to sort the downloads by size (ascending / descending)? Would be good for guys like me who have slow internet to get the small book files first.

EDIT: For myself it wouldn't matter, if the downloader jumps between different bundles to download the smallest / biggest files first.