- UI module triggers 'block-hovered' event
- Toolbar uses 'block-hovered' for appearing
- `currentBlock` setter added to the BlockManager
- (reactangle-selection): the throttling added to the mousemove and scroll handlers
- `getBlockIndex` method added to the Api
- (api-blocks): toolbar moving logic removed from `blocks.move()` and `blocks.swap()` methods. Instead, MoveUp and MoveDown tunes uses Toolbar API

- Toolbox became a standalone class from the editor module. It can be accessed only via the owner (the Toolbar module)
- (api.blocks) the insert() method now has the `replace` param. Also, it returns inserted Block API now.