Upgrade tablesorter v2.16.3 -> 2.17.8
 -- https://github.com/Mottie/tablesorter/wiki/Changes#version-2178-9152014
* Use default filter to put the **Episode** filter into regex mode for better matching
  > Allows you to do things like `Show Name - 5x` to see all the matching items for the season.
* Changed ignore articles from `The|A` to `The|A|An`.
* Add hack for the show 'A to Z' to not ignore the article when sorting.
Merge pull request #877 from thezoggy/dev--tablesorter_update

tablesorter update