Inserting a node or drawing an edge fails when the graph is transitioning after another node insertion or edge drawing

[magjac]

Steps to reproduce:

1. Set the transition duration to e.g. five seconds
2. Without waiting for the graph to transition, insert two nodes , e.g. by clicking the middle mouse button twice OR (which is not that easy) draw two edges OR do any combination of inserting a node and drawing an edge.

Results:

When inserting the second node, the node is not inserted in the text editor, the node is visible on the screen but disappears if the browser window is reloaded and an error like this is shown in the browser console:

Uncaught Error: Expected "}", found: "n3
}..."

When an edge is drawn, the edgeis not inserted in the text editor, the edge is visible on the screen but disappears if the browser window is reloaded and an error like this is shown in the browser console:

Uncaught Error: No edge has been drawn