Bump to 2.9.0~pre18
Insert items after the item it has been dropped on, instead of before.
- This way items can be dropped anywhere in a sequence
- Closes #275
Simplify logic in tree_overview.dragMoveEvent
Improvement to interaction with tree interface
- Add keyboard shortcuts for copying, deleting, etc.
- Add linked copy options
- Add permanently delate option
- Select all items that match a name