If mkdirs fails, print which dir we were trying to create
Add a timeout of 100 seconds on stories.
If the timeout is exceeded, we'll note that in the log
and skip the rest of the site, assuming that the site is broken.
(Hmm, but this may be wrong with Xtraurls or sites like
Longreads where stories come from different sources.)
Add new continue_on_timeout config parameter
to control whether a timeout means we skip to the next site,
or to the next story (true means stay on site, skip to next story).