All status messages will be printed into STDERR and only the results will
continue to be written to STDOUT as documentation suggests. Additionally the
following changes are made:
 - on Buildbot each log entry will have a timestamp to make it easy to measure
   time between status messages printed by test runner, users will continue to
   see just the message itself
 - when devil (or any other module) logs error, they will not be interleaved
   with our own output since logging module is thread-safe
 - critical logs replaced with warning since they do not immediately stop
   the test runner
 - logging.exception is used for all exceptions to get formatted stack trace

TBR=machenbach@chromium.org

No-Try: true
Bug: chromium:838864
Change-Id: I197fcc3bc5890130ce8b35c3e21237f9614fc468
Reviewed-on: https://chromium-review.googlesource.com/1159361
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54851}