support European Intermodal Logistic Unit ILU code (EN 13044-1)

[mrkazoodle]

Hi

This is an extension of the ISO6346 container codes: they use the same format and (how I understand it) calculation of check digits.

The difference is the 4th character: while ISO 6346 allows only UJZ, ILU codes use ABDE and special case K which is used for compatibility with ISO6346 or translating ISO6346 codes into an ILU equivalent.

That should be it: a library that would not check if the 4th character is in UJZ should be able to validate ILU check digits as well.