CommsTarget => CommsRecipient

CommsTargetType is now CommsRecipientType, and
CommsMessage.getTargetType() is now .getRecipientType(). This is to
avoid confusion between the recipient of the message and the target of
the "Go Defend" message.
Fixed PacketReader problem with UnknownPackets

When reading an UnknownPacket, the PacketReader will now move the
pointer to the end of the packet, so that hasMore() returns the correct
value.
AudioCommandPacket now exposes properties

You can now get the audioId and command from the AudioCommandPacket.
EngSetEnergyPacket fix

EngSetEnergyPacket now correctly sets its properties when constructed;
getSystem() and getAllocation() method exposed
More packet unit tests

AudioCommandPacket, CommsIncomingPacket, CommsOutgoingPacket,
IncomingAudioPacket, ToggleRedAlertPacket, EngSetEnergyPacket