Introspection graph visualization with improved node placement

[ksunden]

• New graph visualization tools
• Adjust formatting of introspection plots
• Use introspection plots in Graph.visualize

[story645]

Can you post an example of the viz it produces?

[ksunden]

New for a Line:

Edit: noted after uploading that I moved one node out of frame here and a weird annotation thing happens then, that is an upstream thing that I've made a note to look into further when I get the chance)

Old for a line:

New for an Image:

Old for an Image:

I'm not going to sit here and say there is zero room for further improvement, but I do think they are at least better. (Note that these examples are the only the portions of the overall graphs that are held by the Artists themselves, the Axes is responsible for further edges which are not shown)