BUG: 3350 correct slice offset when fit to volume is called
requested to merge github/fork/HastingsGreer/bug-3350-correct-slice-offset-when-fit-to-volume into master
fixes http://na-mic.org/Mantis/view.php?id=3350 . There are duplicated code paths to call this method, there will be another pull request refactoring to prevent future bugs.