Disabling physics

Hey Andrei!

I've been playing around with ngraph for a while but we've got some issues with the physics. I read the issues on VivaGraphJS and you mentioned pinning the center node but I haven't managed to recreate it. There are two things that we would really like to change: the graph moving outside of the screen and the "wobble". I found and looked at ngraph.forcelayout as well as ngraph.physics.simulator, but trying to include it in my script with the example code provided didn't do anything. https://dpaste.de/wdQ6 this is my script, everything has the proper path provided this time :p for the physics numbers, I just changed them a bit from what's on ngraph.forcelayout but I didn't see any changes. Again, many thanks for your help and I love the framework you've created here!

Start with the linked script and the ngraph.forcelayout and ngraph.physics.simulator examples mentioned in the issue. Determine whether the requested behavior is supported and clarify how to disable or adjust the physics, pin the center node, and prevent the graph from leaving the screen or wobbling.

Written by the indexing model from the issue text.