Improve PDF filenames from the publisher's default

[brunj7]

See if we can rename the file with more explanatory names

[nathanhwangbo]

I started looking into this. My approach is just renaming the file using file.rename() in the for loop of article_pdf_download(). Thinking about using maybe publication year and first author?

[nathanhwangbo]

I have a partial implementation for this, which saves files using (name)(publication year)_(doi).pdf
We can't have backslashes in the filename, so I replaced the \ in the doi with ..

To do

I had to use regex to try and pull out the first author name. Some of the papers start with first name, and some start with last name though, so the name isn't consistent.

We can try to figure out how to consistently pull out the last name.