* Adds a "Tags" field to the post replacement dialog box. The given tags
are added to the post after replacement.
* Prefills the Tags field with certain tags that usually need to be
removed after replacement: replaceme, image_sample, jpeg_artifacts, etc.
Adds a "Final Source" field to the post replacement dialog. If
specified, the post's source field will be changed to this value after
replacement.
This makes fixing the source back to the HTML page after
replacement easier.