Downloading Media from Direct Messages Fails

[johnnybubonic]

This seems to be due to e.g. the goinsta.InboxItem.MediaShare.insta being nil, as I get a nil deref on line 743 of media.go and have confirmed that the pointer is in fact nil on that item.

Temporarily I can workaround by just reimplementing Item.Download() and Instractam.download() directly, as the URLs at least populate.

[felipeinf]

I'm working on a newer, completely rewritten version of this project: https://github.com/felipeinf/instago