add prefix and rename data_type.h.
	data_type.h => cmm_Type.h

add const file.
	cmm_Const.h

add trx_TrxId class. It is identify each transaction and active/passive node sync distribute transaction by trx_TrxId.
	class trx_TrxId.

add trx_UndoBuffer.h file.
	It's not used yet.
rename trx.h file.
	trx.h => trx_TrxId.h