Add patches to make the tests pass with tidy-html5 providing libtidy

debian/changelog

debian/control

...ib-ignore-tidy-html5-s-differently-formatted-summar.patch

debian/patches/series

debian/patches/t-allow-tidy-html5-as-generator.patch

...-don-t-assert-that-tidy-will-add-a-HTML-3.2-doctype.patch

...-unicode.t-don-t-assert-that-the-DOCTYPE-is-preserv.patch

...-use-a-pre-HTML5-DOCTYPE-to-get-warnings-about-unes.patch

...hes/t-venus.t-adjust-expected-result-for-tidy-html5.patch