- '\xFF\xFE' and '\xFE\xFF' are valid, but empty, UTF-16 strings -- don't print a warning
- print a warning on strings that don't start with a valid BOM
BUG:156076
git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@764385 283d02a7-25f6-0310-bc7c-ecb5cbfe19da