Fixed a bug that led to too large steps when scrolling.


git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@940 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Fixed a bug that sometimes cropped the image.


git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@941 ef8490bc-f317-4725-81ed-e95a9aca1bcf