"exit" hangs on terminal version of IPython

[takluyver]

The current HEAD version of the terminal interpreter hangs when the "exit" command is used, rather than exiting.

[takluyver]

(I'd forgotten that pull requests create a new issue automatically. See bug 242)

[ellisonbg]

I just tried to run the test suite on HEAD and it freezes entirely. I have a sneaky feeling that this is related to the issue here. I think we may need to reconsider the usage of threads for the autosave capability. But for now, let's get the test suite working again.

[takluyver]

The tests don't hang after this patch (you're right, it's the same issue preventing shutdown after each test suite). But they do, on inspection, leave some messy thread shutdown errors. I'll see if there's a better way to do it.

[takluyver]

I've updated the pull request, the test suite is running properly again, at least on my computer.