Add option to disable some node from UI

Hi guys,

cheers for this awesome tool. That's a nice start and I would like to see more things in the UI.

I like the D3 graph controls, however I would like to easily "disable" some nodes to visualise more easily my dependencies.

For instance: http://bl.ocks.org/gre/raw/8caa85c90b134f3c8852/ is the graph of my app,
but it is barely readable because basically everyone depends on "react" , "lodash" and "q". I don't want to statically remove those nodes because that's the truth, I just want to disable (delete/or grey out) from the UI a node and all its connection.

Thanks

Start at the D3 graph controls in the UI and trace how nodes and their connections are rendered. Done means a user can disable or grey out a selected node and its connections for visualization without removing it from the underlying dependency data.

Written by the indexing model from the issue text.