Add Trim margins option for report previews. 

Note 1: It just visually removes margins from all previewed pages and should not affect printouts, number of pages or any contents.

Note 2: This wish may be combined with wish #378618 to support multiple page view. 

Note 3: If Continuous pages is present and set (wish #378619) scrolling should still be offered and pages should be vertically centered.

Note 4: If Facing pages is present and set (wish #378620), scrolling should still be offered and pages should be vertically centered.

See attachments for examples from Okular.