Provide better handling of preference for Unicode

[orome]

Figure out a way to either

• better document the expectation that combining Unicode (for state display markup) and Unicode glyphs (for thin Naval rotors) are supported,
• detect whether they are and substitute something else, or
• provide command line arguments or parameters to substitute other characters.

[orome]

The Python 3 version seems not to have this problem, except on Windows, where it is fixed with environment variables.