utils::tokenize_quoted: track escapes more obviously
utils::tokenize_quoted: track escapes more obviously

Previous implementation was unnecessarily clever. I think a clearly
named boolean is easier to understand.

newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat