Add more descriptive error message in icon chooser for timeout

[mlwilkerson]

The default timeout is 5 seconds when making the request. When it times out, there's a vague error message. But it seems to happen often enough that it would be less alarming to just say "timeout: try again", instead of a totally black box fatal-sounding error.

[subhamengine]

Hey, I would like to work on this issue.