Add @move listener

[DrSensor]

Emit move event with SVG.Element as emitted value when moving the annotation.
The event is emitted after the movement is finish.
The use case is when you want to save/send/sync the coordinate of the annotation.

Usage

<v-annotation @move="el => $http.post('/a/1', [ el.x(), el.y(), el.width(), el.height() ])" >