NumeralSystem provides conversions to and from representations in the given system.
NumeralSystem and a number's representation
in that system, return the number.
Err if this function encounters a character not in the system,
or if an int to int conversion fails.
fn encode(&self, val: T) -> Result<String, TryFromIntError>
NumeralSystem and a number, return the
representation of that number in the system.
Err if an int to int conversion fails.
This will interpret signed integers as if their bits represented their unsigned counterparts.