Encoder and decoder for HTML entities, like ρ for ρ. See https://shapecatcher.com/ to identify shapes and also https://detexify.kirelabs.org/classify.html for identifying LaTeX characters (which are not supported here).
decode one entity, and "" empty string is returned when the string cannot be decoded.
utility method for decoding entities like ρ into UNICODE. Malformed entities (like B1; instead of α) are formatted as "???"
encode one or more entities.
return true of the font supports each character of the string.
provide a picker GUI