Allow `display` to accept and display multiple arguments

[yurivish]

This is something I've occasionally wanted: display(foo, bar, baz), similar to console.log.

I think I'd be okay with each result printed on its own line, effectively being equivalent to calling display multiple times.

I'm not sure this is a good idea but I keep writing it and then remembering that it doesn't work so I thought I'd file an issue and see what people think.

[mbostock]

Agreed. I tried this absentmindedly the other day and was surprised the other values aren’t displayed. I’d prefer if they somehow appeared on the same line.