Allow non-ascii identifiers to be used as character names.

There are a couple of caveats here, since non-ascii identifiers
can't be used in python code.

* The names must be defined with the define statement.
* The names can't be accessed in python code.

Stil, something like:

    define 彁 = Character("Boy who is not able satisfactorily to explain what a Hrung is, nor why it should choose to collapse on Betelgeuse Seven")

    彁 "Don't forget your towel."

should work.