Detect invalid input to Code 39 encoder and reject it more explicitly
Detect invalid input to Code 39 encoder and reject it more explicitly

git-svn-id: d565a5fbffec933846bf643895bf9c245569575b@2803 59b500cc-1b3d-0410-9834-0bbf25fbcc57

youknowone/zxing,youknowone/zxing,youknowone/zxing,youknowone/zxing