fix(demo): Row click event is fired when clicking a task

In order to prevent the click event to bubble up to the row the event handler should include a event.stopPropagation().
feat(draw): Enable drawing property can be a function

If the enable property is a function instead of a value then the event parameter is passed. This can be used to activate the drawing only when a certain button is pressed.
feat(task): Enable task move property can be a function

If the enable property is a function instead of a value then the event parameter is passed. This can be used to activate the task move/resize only when a certain button is pressed or the function can be used to check if the task meets a certain condition.