#219 Parsing of HL7v2.3.1 ADT^A04 is not correct

[Anne-Gaelle]

When parsing a message with the following MSH segment :
MSH|^~\&|TEST1|TEST1|TEST|TEST|20071220110853||ADT^A04|200000001|P|2.3.1|201
hapi uses the class ca.uhn.hl7v2.model.v231.message.ADT_A04 but this is not the message structure defined by HL7 for this event, it should be ADT_A01.