Allow P/D & S creation 'always'. See #11048

Also if images are selected on Dataset creation, put images into Dataset
Fixing 404 for unused dropdown_right_arrow.png
Blitz ann.getValue() checks for None. Fixes #10666
check canLink when adding Images to new Dataset
Blitz uses unwrap() to handle null values. See PR #1249
Allow creation of Project & Screen when Project selected
Allow to create P/D/S when Orphaned is selected
Only add 'orphaned' images to new Dataset
return unwrap(self._obj.longValue) from PR #1402
Merge pull request #1433 from will-moore/dataset_creation_11048

Dataset creation 11048