Implement re-ordering of waypoints

[okopanja]

Things to consider:

1. up/down arrows
2. drag & drop

[okopanja]

for drag & drop possible usage off following callbacks should be verified:

• addMouseDownCallback: to start dragging
• addMouseMoveCallback: to move if dragging is in progress. here the row should be completely moved
• addMouseUpCallback: to stop dragging. Possible usage:
• addMouseLeaveCallback