fix missing trailing comma in month match pattern
fix for acm web page

There are two points:

- The id field in the url can be a single number, as in old days.
- The page style is updated, so the CSS selector for bibtex link needs
to be updated accordingly.
add test links in test.md
update To Title Case to v2.1
fix selector for bibtex link on acm page, add a test

We now search the string BibTeX in the sidebar, instead of precise CSS
path, since the contents in the sidebar vary for different pages.
update year in copyright, version 1.0