FIX: check for sample=zero


git-svn-id: https://www.nitrc.org/svn/cmtk/trunk@4871 42a5c34f-2066-0410-bec5-ba365beb4995
FIX: safe string operations
FIX: catch non-existing Vanderbilt image file


git-svn-id: https://www.nitrc.org/svn/cmtk/trunk@4872 42a5c34f-2066-0410-bec5-ba365beb4995