message: Make a note the items are only available in te END_BEFORE
diff: Variable Name Type Notes
  BARTER_TARGET object The other player involved in the barter
  BARTER_COMPLETE int TRUE/FALSE - whether the barter completed successfully
  - BARTER_INITIATOR_ITEM_COUNT int How many items the initiator traded away
  - BARTER_TARGET_ITEM_COUNT int How many items the target traded away
  - BARTER_INITIATOR_ITEM_* object Convert to object with NWNX_Object_StringToObject()
  - BARTER_TARGET_ITEM_* object Convert to object with NWNX_Object_StringToObject()
  + BARTER_INITIATOR_ITEM_COUNT int How many items the initiator traded away, only in _BEFORE events
  + BARTER_TARGET_ITEM_COUNT int How many items the target traded away, only in _BEFORE events
  + BARTER_INITIATOR_ITEM_* object Convert to object with NWNX_Object_StringToObject(), only in _BEFORE events
  + BARTER_TARGET_ITEM_* object Convert to object with NWNX_Object_StringToObject(), only in _BEFORE events
  *///////////////////////////////////////////////////////////////////////////////
  /*
  