Add grace-period to bypass the local tvdb show status 'ended' check.

The bypass introduces a sliding window of +/- 30 days from the
latest aired EP airdate and -30 day before next unaired EP airdate
where we will get the latest data from tvdb.
We exclude season 0 at this time from this check to prevent abuse.
This should prevent the need to do 'force full update' to fix shows
that get their status changed incorrectly while still reducing the
hits to tvdb for shows that are in-fact ended.

Added 'ended' bypass on to prevent older shows with no next aired ep
from being missed (ex Arrested Development or shows that have a
solid year or more between seasons - like Sherlock)
Add last_update_tvdb for controlling nigthly showupdates

+ move setTVRID into own try for correct error log message
Change start options + added help text

+ create pid decision outside loop,
  otherwise using: --pidfile= --daemon is not creating pidfile
+ location pidfile in error output (debugging scripts)
+ rewrite some messages
+ unify exiting with sys.exit
Merge branch 'add_should_update_ended_shows_dev' into development
Fix mixed line endings
Change 90 days update: update only 10 oldest stale shows per session

Distribute the updates of real 'Ended' shows in smaller portions,
prevent hitting thetvdb with all stale 'Ended' in one update session.

+ moved should_update to TVShow object
+ use same update_date variable during session
+ changed some variable names
Fix unnecessary message about PID file creation
Change omgwtfnzb search url (301 Moved Permanently)
Merge branch 'change_90_days_update_dev' into development
Fix AddLastUpdateTVDB wrong subclass (mr-orange)
tablesorter 2.13.3 -> 2.14
Fixes empty dataset sort to how it was before.
Merge pull request #774 from thezoggy/dev--tablesorter_update_fix

tablesorter 2.13.3 -> 2.14
Merge remote-tracking branch 'upstream/master' into offical_dev