Add Unicode support

[jenstroeger]

Hi, considering that the Unicode code points U+2160 to U+217F (part of the Number Forms) define dedicated upper-case and lower-case characters for roman numerals, I’m curious if there are plans to support those.

I could imagine an optional flag unicode_numerals for the two functions fromRoman() and toRoman() which

• when False (default) uses plain ASCII characters, the current behaviour; and
• when "lc" uses the Unicode code points U+217x (lower case) and when "uc" uses the Unicode code points U+216x.

The upper/lower case could also be handled as a separate flag, considering PR #22.

Happy to tinker with a PR, if need be.

[dataflake]

There are no plans, no. This package is in pure maintenance mode. Feel free to apply for contributor status (see https://www.zope.dev/developer/becoming-a-committer.html) and suggest a PR, I'll be happy to look at it.