Fjernet receivedDate. Renamet deliveryDate til deliveryTime.
Fjernet siste rest av receivedDate
Removed receivedDate from MessageBuilder
Renamed deliveryDate
Validates that Documents are not instantiated both with openingReceipt and opened=true
Merge branch 'flytt_post'

Conflicts:
	src/main/java/no/digipost/api/client/representations/Message.java
	src/main/resources/xsd/api_v6.xsd