Time out if initialization doesn't conclude for some reason

[jeffgca]

Similar to #109, we recently had a problem with our infra that caused the WAT UI to just show an infinite spinner. We should have a long-ish ( 10 seconds? ) time out and soem sort of error page shown to the user once the time out gets hit.

[jeffgca]

Aside: probably an opportunity to include some cute illustrations for error pages?