demo

Results 1 issues of demo

A graph showing different root nodes,as this ![image](https://user-images.githubusercontent.com/24200096/54899261-2923f380-4f0a-11e9-9e7f-522a2383d113.png) There is now a requirement, a graph has multiple root nodes, but an error is reported with neo4jd3.js ![image](https://user-images.githubusercontent.com/24200096/54899356-8b7cf400-4f0a-11e9-9392-b37e9251d05f.png)