Refactor test organization and update CI actions

[jassielof]

Mostly organization changes.

• Updated the CI checkout version and names
• Moved unit tests as integration tests to a in/valid structure, I had to do slight changes to the tests, such as changing the use of new() method as it's not public. As for the rest of smoke/dump tests I left them under dumps.rs, I didn't really know what to do with them, maybe under smoke.rs?
  • Fixed Both parse_incorrect_result and parse_incorrect_types tests fail on Windows #95
• Fixed Clippy warnings
• Updated the Types module to the new naming convention.

Some other things I wanted to update were:

• Using the README as the library doc comment

And some other suggestion was a site that has a lot of BibTeX fixtures, which might be useful: https://www.math.utah.edu/~beebe/bibliographies.html

Also, some of his projects might be useful if not referenced yet, for example bibclean or bibcheck or bibparse, etc. Recent versions are GPL 2.0, some older ones are public domain, but if only used as reference work for study I don't think they would affect the licensing of the crate.

Some are C though others are PostScript I think, which doesn’t help.