Parallelized attachment downloading + fixed relative URL bug

[CalderWhite]

Also added .csv and .parquet extensions to valid attachments so you can mass download websites hosting data!

[antsanchez]

Thanks for the changes, but you have changed also github.com/antsanchez/ for github.com/CalderWhite

[CalderWhite]

@antsanchez sorry, that was just for personal use while I was waiting on a response. I can remove that if you are interested in merging in the changes!

[CalderWhite]

I think there also might be an issue where it never closes all the channels because I often have to ctrl+c when I am done downloading. Haven't gotten around to debugging why I can't gracefully exit (likely some issue with the channels + concurrency)

[CalderWhite]

Update on that bug, I just ran it on an ubuntu system and it exited perfectly! I might have fixed the bug and forgotten I did...

[antsanchez]

Hi, thanks again and sorry for the late reply!
Can you change the path: github.com/antsanchez/ instead of github.com/CalderWhite so I can merge the PR?
About the last fixed bug you commented, it is already included on the PR?

[antsanchez]

Hi, thanks again and sorry for the late reply!
Can you change the path: github.com/antsanchez/ instead of github.com/CalderWhite so I can merge the PR?
About the last fixed bug you commented, it is already included on the PR?