Improve Module representation in vizNetwork

[m-l-1]

Box with:

• input ports
• output ports

Nested modules in a meta-node?

See example from https://rawgit.com/iVis-at-Bilkent/cytoscape.js-expand-collapse/master/demo-undoable.html

[jonas-hag]

Could you specify a bit more what you have in mind? Then I maybe could have a look into it.