Option to switch PlexConnect to iMovie Theater / WSJ / Trailers App

Added a config option "hosttointercept". It allows users to switch between the iMovie Theater / WSJ / Trailers App.

hosttointercept=trailers.apple.com            // for Trailers App
hosttointercept=www.icloud.com              // for iMovie App
hosttointercept=secure.marketwatch.com // for WSJ App

It defaults to "trailers.apple.com", so it souldn't break the usual behavior and existing plexconnect tutorials/documentation.