dd_ligbtar_menu.js: Fix for behavior with the item color when printing the...

dd_ligbtar_menu.js: Fix for behavior with the item color when printing the last portion of an item. Also, UTF8 detection improvement.
The menu items have an isUTF8 property, which must be set to true by the developer if it is known that the
item text has UTF-8 characters.  Sometimes (as discovered when listing personal emails), an item might have
UTF-8 characters but the isUTF8 properrty wouldn't have been set to true.  In that case, try to detect whether
the text has UTF-8 using str_is_utf8() (which maybe should always be used instead of the isUTF8 proprety).
Also, this includes an improvement for item formatting with the background color if it still gets into the
'else' case where it thinks the item text doesn't have UTF-8 characters when it actually does.