Ability to delete media and associated files

New and improved PR. Since a few of you have contributed I was thinking to make a PR for SickGear.

Feature: 
Ability to let SickGear delete media files automatically when the status of an episode is changed to the desired state (instantly or with a delay time in minutes to prevent mistakes). The desired state could be archived, ignored or skipped and maybe in the feature a new status: watched. This feature may be useful when you don't have fysical access to your media server, and still would like to delete the watched episodes using the web page or API.

How it works:
1. activate/deactivate ability to delete episodes with a desired state on the postprocess configuration page
2. choose delay time (in minutes) so any mistake in status change can be corrected
3. choose to either delete files permanently or send to trash first so files can be recoverd.
4. after a mistake the planned deletion can be canceled on the displayshow page

There is one thing not working yet, but I don't know you to fix: 

The file ajaxEpCancelDelete.js needs to be created in gui/slick/js to show a loading picture and prevent the page from following the link. I've tried but JS is impossible for me. Maybe someone can help?