Pop-up optimization

[cecilia-donnelly]

@pjsier, do you think it would possible to close the new participant pop-up when the user clicks outside the pop-up or hits ESC? I find myself wanting to close it without moving the mouse all the way over to the "X."

[pjsier]

@cecilia-donnelly yeah, I don't think that should be too much trouble. This StackOverflow answer seems like a straightforward way of doing it https://stackoverflow.com/a/27759070, so I can add that now