Add ability to load/save from URL

[saulshanabrook]

If we are looking at a graph in the visualizer embedded on the egglog editor, it might be nice to be able to share that with someone. We could add the ability to export from the visualizer to a URL that would load it from the hash... Like GZIP and encode the JSON in some efficient way.

Why not just share the egglog code too? Well the other day I was working off a fork of egglog and it would still be nice to able to share the visualized code.