Fix bug, was crashing when using raise/lower tool, update_world was wrong, trying to do things always which should be conditional on there being a tracksprite
Fix bug, was crashing when using raise/lower tool, update_world was wrong, trying to do things always which should be conditional on there being a tracksprite


git-svn-id: 1c5f0d70b70358869d03d7859daa03e4e3c53617@304 741c516a-3ba6-4fa8-b112-5c51f26a88df

tbentropy/pytile