Convert image v4.7 changes: Fixed issue with checking for WEBP support when using GD.
Convert image v4.6 changes: Fixed issue with converting images in conversations.
Convert image v4.4 changes: Added 'Convert conversations' to options page.
Convert image v4.3 changes: Added 'Exclude domains' to options page.
Convert image v4.1 changes: Now supports webp images by converting them to jpg.
Convert image v4.0 changes: Added Extension check to options page.
Convert image v3.9 changes: Code now only runs if post message is new or edited.
Convert image v3.8 changes: Improved corrupt image error handling.
Convert image v3.7 changes: Improved corrupt image error handling.
Convert image v3.6 changes: Fixed issue with strpos empty needle.
