[Feature] Be able to resume from last folder if connection drops

[develroo]

As it stands every time the script is run it will start checksumming all the files, depending on how many files that it is can take 10's of minutes. Furthermore, if a download it then interrupted it will begin again from the beginning check the checksums of all the files.

Can some sort of flag be made to either skip checksumming all the files or to start from a particular bundle/purchase number?

Thanks.