EDIFACT disassemble: Ignore specific segments

Sometimes it could be nice to ignore EDIFACT segments that are not part of the xsd. This is particularly useful for encrypted security segments like USA, USR etc. Because they are defined on message level but are not part of the microsoft xsds.

I suggest that we add a list of segments to ignore to the Edifact disassembler. So you could just add USR, USA, UST, USC etc. Then the disassembler would simply ignore these segments and not throw an error.