/*
* Convert 16-bypte raw signature into a human-readable 36-byte ASCII string.
*
* Used after MusicBrainz::TRM#generate_signature has returned false and
* MusicBrainz::TRM#finalize_signature has returned a signature.
*
* Aliases:
* MusicBrainz::TRM#sig_to_ascii
* MusicBrainz::TRM#convert_sig_to_ascii
*
* Examples:
* puts 'signature: ' << trm.convert_sig raw_sig
*
*/
static VALUE mb_trm_convert_sig(VALUE self, VALUE sig) {