v0.3.0

Added

• The page preview can be zoomed and panned.
• Scrolling over the page preview moves between pages.
• Run page ranges accept all, odd, and even keywords, with quick-select
  buttons for each.

Fixed

• Cropping a PDF page a second time no longer drifts. The new crop is now
  anchored to the current cropbox, so it insets within the already-cropped
  region instead of shifting back toward the original page origin.
• The crop box stays visible when switching between page previews.