Add image in AutoDB returns failure if commit fails
Merge branch 'develop' of github.com:sleuthkit/sleuthkit into develop
Merge branch 'develop' of github.com:sleuthkit/sleuthkit into develop
Manual merge from #318 to develop branch.  Code from @simsong with pull request title of Fixes hashing of sparse files and eliminates warnings
manual merge into develop branch from #306 from @joachimmetz to add external type to image layer