Release v4.0

Release v4.0 is a major code overhaul that introduces the following new features and improvements:

Ignore list: shortens time required to find new files on script execution by excluding files the script has already successfully processed
Clone audio to stereo track: Addresses #42 - when enabled, will create a stereo copy of any non-stereo audio tracks for each file for playback on stereo systems (while retaining the original audio track)
Metadata title: Sets the file's metadata title to the filename (helps with Plex matching) [thanks to @djgrijalva]
User-defined failover threshold: User can now define the failover threshold to any desired percentage (Addresses #38)
Failed encoding reporting: List files that failed to encode (even after failover) in the log
Corrupt file reporting: List corrupt files in the log (files with either corrupt video or audio codecs)

Configuration: Configuration is now set by the user in a plain text file
Code enhancement: Code is now modular, increasing readability and ease of adding new features
Portability: Pulling the latest version of the code will not overwrite or otherwise change any user settings in the config file
Validation: All user-defined settings in the config file are validated prior to the script executing. Any errors will cause the script to log a relevant message and exit.
Timekeeping: Fixed various issues with timekeeping in the script, resulting in more accurate statistics
Best practices: Various changes to conform to Powershell best practices

Provide feedback