arrows app integration

[seb-esser]

Hi Jakob, Here's another code snippet for IFC data visualization in a graph-based fashion. The arrows tool is a nice app to interactively create graphs and then bring them into neo4j or to a graphML representation. I am mainly using it for illustrations in teaching or publication resources. I am unsure if you'd like to grow your repository towards such things as well. If not, feel free to suggest any other place where it may fit better. Best Sebastian