[Server][DataStoreEventProc] Remove an unnecessary include line.
[Server][DataStore] Add a new virtual function: setCopyOnDemandEnable()
[Server][UnifiedDataStoreEventProc] Add a new structure:
UnifiedDataStoreEventProc
[Server][DataStoreEventProc] Include "UnifiedDataStoreEventProc.h"
[Client][Servers][Users] Use HatoholItemRemover.