Add write is_delete in DB
1.Add DB APIs: findByUri,getItemByUri  2.Modify DB API: updateItemValue  3.Modify addFile/rmFile for combine with DB  4.Fix bug: crash when open data
Merge branch 'Data' of ssh://github.com/IbpTeam/demo-rio into data#40_wangfeng
Merge pull request #117 from v11985/data#40_wangfeng

Add write is_delete in DB ->xiquan