UserMessage base class, ContactPeersMessage is now a separate UM
added RequestUserMessage abstraction for UMs with a response
minor changes
GetNextFromQueueMessage finished, RequestUserMessage received some
necessary helper methods
ContactPeerUserMessageTest
GetNextFromQueueMessageTest (not working yet)
extended IRequestMessage interface, defined DirectRequestMessage and
RoutedRequestMessage
refactoring of messages and user messages
GetNextUserMessageMessage test re-implemented (not working yet)
minor refactoring in messages
encryption/decryption methods and comments how it would be done, not
finished yet
encryption/decryption methods and comments how it would be done, not
finished yet
Small changes...
further testing, added SerializableLinkedList
Fat bug fix in tests! Try to avoid private classes. They serialize
parent classes references too...
message future listeners renamed
Merge branch 'um-queue'

Conflicts:
	org.hive2hive.core/src/org/hive2hive/core/process/login/SynchronizeFilesStep.java
Refactoring and extension for fully encrypted messages. Some test are
still failing.
Random git merging stuff...
Merge remote-tracking branch 'origin/master' into message-encryption

Conflicts:
	org.hive2hive.core.test/src/org/hive2hive/core/test/network/messages/BaseMessageTest.java
	org.hive2hive.core.test/src/org/hive2hive/core/test/network/messages/BaseRequestMessageTest.java
	org.hive2hive.core/src/org/hive2hive/core/network/NetworkManager.java
	org.hive2hive.core/src/org/hive2hive/core/network/messages/futures/FutureDirectListener.java
	org.hive2hive.core/src/org/hive2hive/core/network/messages/futures/FutureResponseListener.java
	org.hive2hive.core/src/org/hive2hive/core/process/common/messages/BaseDirectMessageProcessStep.java
	org.hive2hive.core/src/org/hive2hive/core/process/common/messages/BaseMessageProcessStep.java
	org.hive2hive.core/src/org/hive2hive/core/process/login/ContactPeerMessage.java