7_Networks.ipynb unusably slow?

[jbednar]

Maybe it's just my system somehow, but the interactive plot at the end of 7_Networks.ipynb is unusably slow, and I assume it hasn't always been that way, or else we would have drastically simplified the example. Right now the Bokeh plot updates seemingly much more quickly than the Datashader version, which takes minutes to redraw on pan or zoom and leaves it looking like this in the meantime:

[ablythed]

This happens for me too, so I don't think it's a system issue. It took 5 or 10 minutes to get here:

Then two or three more to get here, which is better, but still seems low resolution: