Changed Gson and Akka to newest version.
Separated Hazelcast tasks, Akka messages and Gson objects. Added matching StreamSerializer classes for all Hazelcast tasks. Used submitToKeyOwner to handle tasks on correct cluster node (PartitionAware in task was not correct). Removed userID from DocumentMetadata so StorageJsonController can be used statically. Created base classes for Akka messages and callbacks. Created manager classes for InazumaStorage and Hazelcast. Moved getRequestController() and getStorageController() from Main to manager classes.