multiple_choices vs multiple_choices_redirect

[sk1p]

While working on #183 and wondering why some tests take a long time, I noticed a bug in TestMultipleChoicesRedirects - the test accesses /multiple_choices_redirect/ but the SimpleApp server only defines /multiple_choices/ - so in this case, it falls back to the default 200 response in __call__. This may be hiding a real bug, I didn't really investigate further.

Maybe it would be a better idea to return a 404 or 500 error in cases of unknown URLs