Ensure that node names don't contain leading/trailing whitespace or commas, and do contain non-whitespace characters

[fedarko]

Relates to searching, which I'm currently rewiring back in. This really shouldn't be a problem for most graphs, but I don't believe we explicitly guarantee this anywhere. The reason is that, when the user searches for stuff in the browser, it's natural for them to enter something like

nodeABC, nodeDEF, nodeGHI

... in which case we can figure out the node names they mean by splitting at commas (,) and trimming leading/trailing whitespace. That's all fine. But if any of the node names actually include leading/trailing whitespace, or if they only contain whitespace (lord I hope not), or if they contain commas, then this'll break things.

The solution is really just adding an extra validation step that goes through and checks this. As mentioned, this really shouldn't be a problem, but it's good to be safe.