fix IOError handling
Add urwid stop prior to stack trace so exceptions are not cleared from screen
Merge pull request #343 from deployable/master

Add urwid stop prior to exception output so stack trace is not cleared
fix #344
remove outdated IOError test case (https://github.com/mitmproxy/netlib/commit/f5fdfd8a9f17e0fe213a9cf54acae84e4bc31462)
Merge branch 'master' into issue_341