[Easy] If position values are strings, draggable behavior is erratic

[mikeqci]

Values passed as strings will cause extremely erratic dragging on first drag

<div ngDraggable [position]=" {x: '100', y: '100'}" ></div>

Same values passed as int/float will cause normal behavior

<div ngDraggable [position]=" {x: 100, y: 100}" ></div>

This is tricky to debug when using dynamic values (like loading a saved value, for example)

This library is awesome, thanks for all your hard work!