Re-implement apply general script
Add split-view icon
Re-implement purge unused items functionality
Drag-and-drop improvements
- Support copy paste
- Support copying items between different instances of OpenSesame
Remove deprecated references to main_window.refresh()
Catch osexceptions when applying item script
Clean loop code
- Prevent edit-apply recursion
Initialize user-hint widget
Remove sanity check from qtitem
Initial pass at validator package
Clean-up loop controls
Migrate all core items to cleaner framework