Codegroup converts any file, of any format including raw binary,
 into a set of five letter uppercase codegroups.
 The codegroup format includes a 16 bit CRC and file length to verify
 message integrity.
 Codegroup does NO CRYPTO. It's purely a file format converter
 much like base64 or uuencoding.
 Unlike other traditional file encoding algorithms such as
 base64 or uuencoding, codegroup exclusively uses the 26
 letter alphabet.
 Codegroup is ideal for transferring short binary files over a voice
 or morse code channel.