Breaking change for persisted JSON data (e.g. in a file or database): I've simplified the JSON export format and broken backwards compatibility with v0.3.0 JSON export format. Substantially the format is unchanged with only minor changes to the outer object namespaces. Latest looks like this:

var digraph = new jsgraph.DirectedGraph()
digraph.toJSON()
'{"jsgraph":{"digraph":{"vertices":[],"edges":[]}}}'