#12 Exception during ACK when handling pre-2.3.1 messages (patch included)

[Fred]

Somewhere prior to HL7-2.3.1, MSH-9 only contained a message type and did not include the ^trigger event^message structure components. When receiving a message without MSH-9.2, an array index exception is triggered when it attempts to insert message[0][8][1] into the ACK.

This patch checks if message[0][8] has more than 1 component, and if so uses ACK^trigger event for the response. Otherwise, it uses ACK for the response.