Fix for issue #209: stop logging tracebacks for raised Responses.
Let raised Response(3xx)s pass through the whole resource process the same way that Response(2xx)s do.
Add back logging of 5xx tracebacks, and only skip simplates for 2xx and 304 codes.
Merge pull request #217 from nejstastnejsistene/issue209

Fix for issue #209: stop logging tracebacks for raised Responses.