Changed src root directory to the same one as Engine and RestfulServer.
Specify client as module children.
Fixed a bug that no tile is discarded when AI users try to set richi at second time or later.
Added log message.
Changed implementation.
At previous implementation, Engine threw an exception when read message go ahead of write a message.
But that is not necesarry. Engine stopped to throw exception and increment number so that message can be read after write message catch up.