the notate script can be more optimized

[linnabraham]

In the notate script isn't it wasteful to check the doi info every time I would like to take a note on particular paper? Doesn't that also mean the script wouldn't be helpful if am not internet connected? I refactored the code in the initial part of the script to be only executed if there isn't already a .md file present.

NB: I don't know if this is an issue or more of a suggestion.