ParserOptions::setWrapOutputClass().
* Added 'ChangeTagsAllowedAdd' hook, enabling extensions to allow software-
specific tags to be added by users.
-* File storage backends that supports headers (eg. Swift) now store an
- X-Content-Dimensions header for originals that contain the media's dimensions
- as page ranges keyed by dimensions.
* Added a 'ParserOptionsRegister' hook to allow extensions to register
additional parser options.