### Changed
Moved connector label moving logic from `default-tool` to connector view.
#### Other infrastructure changes:
- Gfx element view now can handles drag events
- Added `context.preventDefault()` support to bypass built-in interactions in extension
- Handle the pointer events in element view will bypass the built-in interactions automatically
> The built-in interactions include element dragging, click selection, drag-to-scale operations, etc.
### Change
- Rename `ElementTransformManager` -> `InteractivityManager`
- Now you can `event.on` and `action.onXXX` method to extend interactivity behaviour. The old approach of overriding methods directly is deprecated.
