The rendered style and bounding box for an edge may become stale
The rendered style and bounding box for an edge may become stale

The rendered style may be stale after a connected node is repositioned.  Because the rendered style of an edge is not dirtied when a node is moved, we should force the rendered style of the edge to be recalculated when the bounding box is requested and there is a diff detected for one or both node positions.

Behaviour without patch: Edge labels can be shown at the wrong location.  Edges can be not shown at all for certain pan and zoom levels.  In both cases, a stale rendered style results in a stale bounding box.

Ref #2238

cytoscape/cytoscape.js,cytoscape/cytoscape.js