CHG: index by number, not string

git-svn-id: https://www.nitrc.org/svn/cmtk/trunk@5021 42a5c34f-2066-0410-bec5-ba365beb4995
FIX: check sform AND qform

git-svn-id: https://www.nitrc.org/svn/cmtk/trunk@5022 42a5c34f-2066-0410-bec5-ba365beb4995