Added logback

logback allows logging to file and logcat simultanously (and
many other log destinations actually). If we need to we can
asks users to send the log files that logback generates to
troubleshoot sync errors.
Fixed sync all

Even when all is enabled, the sync would skip subreddits that
where not in the list of enabled subreddits because there was a
typo in the ALL_KEY for the CheckListPreference.
Updated subreddit list