Allow velocityDecay to be set during simulation of the graph

[sudheesh001]

Currently it looks like I cannot pass the velocityDecay parameter via the options of neo4jd3. It'd be a nice feature to include the ability to have velocityDecay as options which can then be sent to the forceSimulation() call in d3

Also, an added nice feature would be to ensure that the edges between the nodes do not overlap when the velocityDecay is closer to 1

Additionally, it might be better to pre-render the entire simulation if possible 👍

Thanks for the great tool.

[StoneStrawberry]

How does your text work in the middle of the connection?

[sudheesh001]

@StoneStrawberry My text in the middle of the connection does overlap with another edge.