Convert image 5.2

Convert image v4.2 changes:

Now retains IMG bbcode options.

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.

Convert image v3.5 changes:

Added Exclude domain to options page.

Convert image v3.4 changes:

Added support for $config['http']['proxy'] in order to allow hiding IP address.

Convert image v3.3 changes:

Code refactoring update.