could box_ul(), box_dl() check the SHA?

[ijlyttle]

This was a question from @ashirwad at the ISU Graphics Group presentation.

Just like box_push() and box_fetch(). This could avoid unneeded transfers.

[sschooler]

I'm not sure what SHA means, but it would be helpful if box_fetch could take a string to only selectively download files with that string in their names. Also, an option for a progress bar or a verbose print-out (e.g. print out the names of files as they are downloaded) would also be really useful. I can open a new issue for these if that would be appropriate.