feat(labels): Add missing row labels resizeBegin and resizeEnd api events

Add missing api events for resizing the row labels area and removed stopEventPropagation on rowLabels from demo in order to allow the user to resize the labels easier.
bug(task): Task goes out of sync with mouse when moving between rows

When a task is moved between row the task position gets out of sync with the mouse position. This happens because the task (incl. moveable code) is re-initialized because of the scope change.