- Move some method parameters into a class attributes.
- use some methods to do the work.
	Move the Logging example to the new version of Dao class.
	Fix some problems when the Dao class generate an exception.
Added new private method Dao::_doWrite
The method Dao::doInsert() and Dao::doUpdate() now execute Dao::_doWrite()
Merge branch 'DaoImprove'