app: do not stop the measurement when straightening.
Instead just transform the measurement extremities appropriately to still map to the same points. To do so, I also added out parameters to gimp_image_resize_to_layers() so that calling code can get offsets from old origin (as well as new image dimensions). (cherry picked from commit d56a8d439e7b799922cab88d502d690453a09630)
Showing with 43 additions and 5 deletions