Fix cl-charms high level API character conversion

Currently as pointed out in the FIXME comments in the code cl-charms is doing code-char and char-code which often does not correctly map the C chars to the equivalent lisp chars.

One problem in particular is the arrow keys map completely wrong.

I will make a pull request for this if I have time/decide not to just use the low level API but thought this should be officially filed.

See https://github.com/HiTECNOLOGYs/cl-charms/blob/master/src/high-level/utilities.lisp#L22-L31.