[FEATURE REQUEST] : option to not crop the covers

[projectorphones]

It would be useful to add an option to exclude the covers from the cropping process, as they are most of the time artworks that people would most likely want to preserve.

[projectorphones]

In the same idea, it would be nice to have the option to exclude the cover from all the processing. For example stretch/upscale can be desirable for all the pages, but not for the cover as it adds borders to it.