Allow items in drawers to be reordered

Reorder items in drawers by dragging them up & down (somehow the same as Published Ports - Input reordering but for the drawers).

Would allow us not to have to replace and reconnect some cables. This could perhaps happen only if you dragged the part of the item where the number is located (screenshot)).

2016-02-22 22.38.14.png

Opened for voting.