Added new queries and new test cases

[EssentiallyNoah]

Adds support for new queries taking advantage of the new features mentioned in #2 including:

• get_multiple_works - Fetching multiple works (uses new OR operator)
• get_related_works & get_referenced_works - Fetching referenced & related works
• get_cited_by_works - Fetching works citing the given work (uses cursor-based paging and lets user limit the number of results)

[dpriskorn]

Big thanks for this PR. I really like way you implemented the cursor and paging. Thanks for the tests also :)

[EssentiallyNoah]

@dpriskorn is there a good way to amend authorship on the PRs? The commit username is incorrect. I've amended the branches on my fork and can re-submit the PR, but am not sure if that would cleanly overwrite a PR that has already been merged.

[dpriskorn]

@dpriskorn is there a good way to amend authorship on the PRs? The commit username is incorrect. I've amended the branches on my fork and can re-submit the PR, but am not sure if that would cleanly overwrite a PR that has already been merged.

I don't think so. What about we adopt the style of Guix and maintain a header in each file with copyrights with the name of all contributors? Like so: '# Copyright 2022 Dennis Priskorn, x, y

[dpriskorn]

I went ahead and added a header to all files. Feel free to send a PR to add your name to the files you edited.