Firefly graphs get stuck and tab has to be killed/refreshed

[tomelm]

Not sure if this is related to #81 but every so often our graphs will get stuck and stop updating. It seems like there might be a memory leak somewhere as we sometimes have to kill the tab in Chrome to get it working again.

I'll try to investigate more next time it happens. I wanted to open the issue in the meantime in case you guys have a fix or this or know what might be causing it.